A Beer at the Hockey Arena Costs $5 Each

A beer at the hockey arena costs $5 each. According to the rule of rational choice, when will Cynthia stop drinking beer?

A) when the marginal benefit received from consuming peanuts with beer just equals $5
B) when the marginal cost of an additional beer is less than $5
C) when the marginal benefit of an additional beer equals zero
D) when the marginal benefit of an additional beer falls below $5