A monopolistically competitive$$ firm's demand curve $($D$),$ marginal revenue curve $($MR$),$ and marginal cost curve $($MC$)$ are illustrated in the figure.

Part $2$

Is this firm maximizing profits if it chooses to produce $7$ units of$$ output? Explain.

Part $3$

If the firm chooses to produce $7$ units of$$ output, then it is