Three of the Four Events Described Below Might Reasonably Be

Three of the four events described below might reasonably be expected to shift the demand curve for beef to a new position. One would not shift that demand curve. The single exception is a(n) :

A) change in people's tastes for beef.
B) increase in the money incomes of beef consumers.
C) fall in the price of beef.
D) change in the price of a product competitive with beef (e.g. pork) .