Suppose That the Extra Cost to Tim of a Third

Multiple Choice

Suppose that the extra cost to Tim of a third glass of soda is zero because he's at a restaurant that gives free refills. According to the Cost-Benefit Principle Tim should:

A) drink a third glass of soda.
B) drink a third glass of soda if the extra benefit of doing so is positive.
C) drink a third glass of soda if his total benefit from drinking soda is positive.
D) not drink a third glass of soda.