You will be given a definition of a task first, then some input of the task.
You are given a short paragraph, a question and two choices to answer from. Choose the correct answer based on the paragraph and write the answer(not the key).

Paragraph: To reduce friction, oil is added to the engine.
 Question: Jeff should add _____ to his engine to decrease the friction in its processes. 
 Choices: A)oil 
B)gas
Output:
gas