A Perfectly Competitive Firm's Short-Run Supply Curve Is Determined by the Equation

A perfectly competitive firm's short-run supply curve is determined by the equation:

A) P= AC where $P \geq \operatorname { SMC }$ . Otherwise, supply is zero.
B) P=AVC where $P \geq \operatorname { SMC }$ . Otherwise, supply is zero.
C) P=SMC where $P \geq A C$ . Otherwise, supply is zero.
D) $P = S M C$ where $P \geq A V C$ or $P \geq A N S C$ or $P \geq S A C$ , depending on the level of sunk costs. Otherwise, supply is zero.