Answer:
a. fall to 0.
Step-by-step explanation:
When a good is perfectly elastic, a rise in the price of the good would make the demand for the good to fall to zero .
The demand curve for a good with perfect elasticity is horizontal.
If the demand for a good is perfectly inelastic, a change in price has no effect on the quantity demanded.
Demand is inelastic when a change in price has a little effect on the quantity demanded.
Demand is elastic when a change in price has a great effect on the quantity demanded.
I hope my answer helps you.