Answer:
a. increase by 2.5%, and X is an inferior good.
Step-by-step explanation:
The income elasticity of demand is the ratio between the percentage change in demand and the percentage change in income.
The change in demand caused by a 5% decrease in income is:
Demand will increase by 2.5%. A good whose demand increases when consumer income decreases is called an inferior good.
Therefore, the answer is a. increase by 2.5%, and X is an inferior good.