11. A manufacturing firm produces gadgets and incurs fixed costs of $2000 and variable costs of $3000 for producing 100 units. The firm decides to increase production to 150 units, which increases the total variable costs to $4500. Choose the correct statement(s) about the firm's production costs from the following: (A) The average total cost per unit decreases as production increases from 100 to 150 units. (B) The average variable cost per unit remains constant as production increases from 100 to 150 units. (C) The total cost of producing 150 units is $6500. (D) The marginal cost of producing the 150th unit is $30.