Fred Buys More Baseball Tickets and More T-Shirts When the Price

Multiple Choice

Fred buys more baseball tickets and more t-shirts when the price of baseball tickets decreases. What explains why Fred buys more t-shirts?

A) the income effect because Fred's purchasing power increased
B) the income effect because Fred's purchasing power hasn't changed
C) the substitution effect because the price of t-shirts decreased relative to the price of baseball tickets
D) the substitution effect because baseball tickets and t-shirts must be substitute goods