If a perfectly competitive firm is producing at a level of output where price is greater than average total cost, what is true

For a firm that uses the weighted average method of process costing, which of the following must be true? (a) physical units can be greater than or less than equivalent units. (b) physical units must be equal to equivalent units. (c) equivalent units must be greater than or equal to physical units. (d) physical units must be greater than or equal to equivalent units.