Answer
B.
Mean that MR5 exceeds MC at Q3 units, inducing the firm
to expand output to Q5.
Work Step by Step
At P3, firm was producing Q3 because that is where MC and MR intersected. When price went to P5, producing only Q3 would mean that MR is greater. According to profit maximizing rule, firm should produce at MC=MR. Therefore, the firm will produce at Q5.
