Carson Wood Products processes logs into four grades of lumber totaling 500,000 board feet as follows at a joint cost of $300,000 Grade First and second No. 1 common No 2 common No. 3 common Board Feet 75.000 200,000 100,000 125,000 Final Sales Value $ 56,250 180,000 105,000 127,500 What amount of joint costs will be allocated to No. 3 common if the constant gross margin percentage method is used? a. $135,000 b. $168,750 c. $45,900 d. $81,600