Suppose the Long-Run Supply Curve for a Good Is Upward-Sloping

Multiple Choice

Suppose the long-run supply curve for a good is upward-sloping. The upward slope could be explained by

A) decreases in production costs resulting from more firms coming into the market.
B) a breakdown of the "free entry and exit" feature of competition.
C) a breakdown of the "price taking" feature of competition.
D) the fact that a resource used in the production of the good is available only in limited quantities.