Both Sally and Sam receive a 10% raise in a single year. Sally increas

Both Sally and Sam receive a 10% raise in a single year. Sally increases her demand for ground beef whereas Sam decreases his demand for ground beef.

A) This is impossible.
B) This is only possible if Sally considers ground beef an inferior good, and Sam views it as a normal good.
C) This is only possible if Sally has lower income than Sam.
D) This is only possible if Sally considers ground beef a normal good and Sam views it as an inferior good.

ANSWER

D