Does a Competitive Long-Run Equilibrium Require Cost-Minimization

Multiple Choice

Does a competitive long-run equilibrium require cost-minimization?

A) Yes, if firms fail to be as efficient as their competitors, they are driven out of the market.
B) No, in the long run, firms make zero profits.
C) Yes, if they didn't, even less efficient firms would enter the industry.
D) No, because competition ensures their survival.