Refer to the information below to answer questions 7-9: Monsters Inc. produces a line of life-size stuffed monster toys. The following are their costs for the last month: Further, last month Monsters Inc. produced and sold 2,000 units at a sales price of $50 each. 7. What was Monsters Inc.'s contribution margin per unit last month? a. $10.00 b. $3.5 c. $22,000 d. $11 8. What was Monsters Inc.'s period cost per unit last month? a. $46.50 b. $6.50 c. $7.50 d. $40.00 9. What was Monsters Inc.'s gross margin per unit last month? a. $10.00 b. $3.50 c. $22,000 d. $11