C. 60
Explanation:
Producer's Surplus means the value producer derives from selling goods. For example, if producer is willing to sell the product for a price 8 but consumers are willing to pay a higher price, let's say 20, then producer achieves a surplus of 12 per unit. Let's calculate the producer's surplus -
As per question, Reservation Price (RP) =20, Price (P) =8, & Quantity (Q) =10
The formula for Producer Surplus (PS) is as follow:
PS = 1/2 (RP - P) x Q
= 1/2 (20-8) x 10 = 60