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) increases 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) a stable demand curve for the good, that is, a demand curve that never shifts.