When the Local Used Bookstore Prices Economics Books at $100

Multiple Choice

When the local used bookstore prices economics books at $100 each,they generally sell 70 per month.If they lower the price to $70 each,they sell 90.Given this,what is the elasticity of demand for economics books,and what action should the store take

A) 2.91; the store should lower prices to raise total revenue.
B) 2.91; the store should raise prices to raise total revenue.
C) 0.714; the store should lower prices to raise total revenue.
D) 0.714; the store should raise prices to raise total revenue.