Answer: a. fall in the price increases the total revenue
Step-by-step explanation:
When Demand is considered Elastic, the quantity demanded of a good changes by a larger percentage than the change in price.
That means that if the price rises, there is a greater reduction in Quantity Demanded then the price.
Conversely, if there is a Price reduction, the Quantity Demanded increases more than the price reduction.
Using the Total Revenue Formula (quantity of goods sold multiplied by the price of the good) then, revenue will rise.
I have attached a graph that shows the impact of prices changing and it's effect on Quantity Demanded. Notice how wider the spaces between the Quantity Demanded and the Prices are.