Holding all other factors constant and using the midpoint method, if a tractor manufacturer increases production from 80 to 100 units when price increases by 15 percent, then supply is

a. inelastic, since the price elasticity of supply is equal to 0.68.
b. inelastic, since the price elasticity of supply is equal to 1.48.
c. elastic, since the price elasticity of supply is equal to 0.68.
d. elastic, since the price elasticity of supply is equal to 1.48.

d