Assuming a product can be manufactured competitively without any externalities at an efficient quantity of 500 units and an efficient price of $150.00 per unit, what efficient quantity-price net subsidy combination would be consistent with a corrective subsidy for a positive externality?

Group of answer choices

a 700 units, $100.00 per unit price net subsidy.

b 500 units, $150.00 per unit price net subsidy.

c 300 units, $120.00 per unit price net subsidy.

d 600 units, $160.00 per unit price net subsidy.