Answer the following question: Question: Sara closed her computer and absentmindedly pushed a paper towel roll across the plastic computer lid. Then she pushed the paper towel roll across a couch cushion. She quickly realizes that the paper towel roll moves more easily on the plastic computer lid than it does on the couch cushion, which she concludes is because there is more friction on (A) the couch cushion (B) the plastic computer lid.  Do not use A and B to answer the question but instead, choose between "plastic computer lid" and  "couch cushion".
Answer:
plastic computer lid