Detailed Instructions: In this task, you're given a question, along with three passages, 1, 2, and 3. Your job is to determine which passage can be used to answer the question by searching for further information using terms from the passage. Indicate your choice as 1, 2, or 3.
Problem:Question: How long had Hafez al-Assad been the President of Syria for by the year he sent troops into Lebanon to fight PLO forces? Passage 1:PA 741 begins at an intersection with PA 722 in the borough of East Petersburg in Lancaster County, heading to the south on two-lane undivided Lemon Street, which is unsigned and locally maintained. The road passes homes prior to crossing into East Hempfield Township, where it becomes Rohrerstown Road and continues through industrial parks. PA 741 gains a center left-turn lane and becomes signed at the Commercial Avenue intersection. The route continues to an interchange with PA 283, at which point it becomes state-maintained. The road crosses the Little Conestoga Creek into Manheim Township after PA 283. The route becomes two lanes again and turns east prior to turning southwest and crossing the Little Conestoga Creek back into East Hempfield Township. At this point, PA 741 becomes McGovernville Road and comes to a bridge over Norfolk Southern's Lititz Secondary and Amtrak's Keystone Corridor. The road passes a mix of homes and woods as it comes to the Harrisburg Pike intersection, where it makes a turn to the south onto Rohrerstown Road, a three lane road with a center left-turn lane. PA 741 passes homes to the west and a branch of Lancaster General Hospital to the east prior to coming to the US 30 interchange. In the area of the interchange, PA 741 is briefly a divided highway. Following US 30, the route becomes a two-lane undivided road and passes residences prior to crossing Norfolk Southern's Columbia Secondary and entering the residential and commercial community of Rohrerstown. Here, PA 741 crosses PA 23. After leaving Rohrerstown, the road passes a mix of farms and businesses prior to an intersection with PA 462. 
 Passage 2:Blignaut went to the State School in his birthplace Paarl, where he subsequently attended the Gymnasium (Grammar School). After his exams Blignaut went to Cape Town, where he joined the colonial administration. In 1861 he passed the examination for the State Service Certificate of the Cape Colony and in 1862 he moved to the Orange Free State. Here he was appointed to the position of clerk to the Landdrost and Justice of the Peace of Philippolis (17 September 1862). At the time, civil, judicial, and military administration were still very much in the same hand. In view of Basotho threats, President Brand ordered the reorganisation of the Orange Free State defence, and the formulation of clear regulations for the different Volunteer Corps, which were administered by the Landdrosts' offices. For Philippolis Blignaut and J.G. Fraser attended the conference.
 Passage 3:According to historians William Cleveland and Martin Bunton, Beirut became an international banking center because of its “laissez-faire economic system”. Business owners from Cairo, Damascus, and Baghdad moved to Beirut for economic opportunities. Despite Lebanon’s cultural liberalism and economic prosperity, sectarian tensions remained as citizens identified themselves through their sects. With Muslims calling for greater representation and with Cold War tensions, Lebanese leadership had to decide whether to ally with the West or with Egypt, Syria and its Arab history. Christians wanted to continue alliances with the West but Muslims were drawn to Nasser's pan-Arabism. Multiple factors including sectarian tensions and Palestinian refugee settlement in southern Lebanon contributed to the beginnings of the Lebanese Civil War. In 1976, Syrian President Hafez al-Assad sent troops into Lebanon to fight PLO forces on behalf of Christian militias. This led to escalated fighting until a cease-fire agreement later that year that allowed for the stationing of Syrian troops within Lebanon. The Syrian presence in Lebanon quickly changed sides; soon after they entered Lebanon they had flip-flopped and began to fight the Christian nationalists in Lebanon they allegedly entered the country to protect. The Kateab Party and the Lebanese Forces under Bachir Gemayel strongly resisted the Syrians in Lebanon. Following the Israeli invasion into Lebanon in 1982, new Lebanese President Amine Gemayel sought the support of Syrian troops to stabilize the region. Syria fought Israeli troops after the latter's invasion of Lebanon.

Solution:
3