Suppose there are 11 buyers and 11 sellers, each willing to buy or sell one unit of a good, with values {$14, $13, $12, $11, $10, $9, $8, $7, $6, $5, $4,}. Assume no transaction costs and a competitive market. At the optimal bid, ask spread, what is the total profit that the market maker makes?

Suppose there are 11 buyers and 11 sellers, each willing to buy or sell one unit of a good, with values {$14, $13, $12, $11, $10, $9, $8, $7, $6, $5, $4,}. Assume no transaction costs and a competitive market. At the optimal bid, ask spread, what is the total profit that the market maker makes?

$8

$12

$18

$20