Answer:
a normal good
Explanation:
A normal good is one that a consumer buys normally and when there is an increase in his income there is an increase in the demand of this good.
The opposite of this is an inferior good whose demand falls sometimes to zero as income increases. Consumers choose other goods to consume as income increases.
In the given instance where Joshua's income increases and he purchases more prime-rib dinners than he did before his income increased, this is a normal good for him.
