Use the Following to Answer Question(s)

Use the following to answer question(s) :
Exhibit: Supply: Short and Long Run

-(Exhibit: Supply: Short and Long Run) S₃ would be the _______-run supply curve if _______.

A) long; expanded production leaves production costs unchanged
B) short; expanded production changes production costs
C) long; there is no entry into or exit from the industry
D) medium; costs are changed if there is easy entry