Suppose the price of university sweatshirts increases from $10 to $20 and the quantity supplied increases from 20 to 30. The price elasticity of supply, using the midpoint formula, is:

Suppose the price of university sweatshirts increases from $10 to $20 and the quantity supplied increases from 20 to 30. The price elasticity of supply, using the midpoint formula, is:
A) 0.66.
B) 1.50.
C) 0.60.
D) 1.66.