When Joe's Income Is $100 Per Week, He Spends $20

Multiple Choice

When Joe's income is $100 per week, he spends $20 per week on pizza. When his income rises to $110 per week, he spends $25 per week on pizza. If the price of pizza remains constant, this information implies that for Joe:

A) pizza is a normal good and a luxury.
B) pizza is a normal good and a necessity.
C) pizza is an inferior good, since his expenditure rose by less than the increase in income.
D) demand for pizza is price-elastic.