Can you go more in depth on how the answers for these two questions are b and d

Figure 2: A monopoly firm 10 Marginal cost Average total cost UT Price w Demand N 0 Marginal revenue 0 1 2 3 4 5 6 7 8 9 : 10 11 12 13 14 Quantity Suppose that Spock is a monopolist who faces the marginal cost, average total cost, demand, and marginal revenue curves shown in Figure 2. 17. Refer to Figure 2. Spock's profit-maximizing quantity is units and the price is A) 6; $4.00 B) 6; $7.00 C) 8; $6.00 D) 4; $8.00 18. Refer to Figure 2. Calculate the area representing consumer surplus if Spock produces the profit-maximizing quantity. A) $16.00 B) $27.00 C) $12.00 D) $9.00