Answer:
Total surplus = Â 4000
so correct option is D. $4000
Explanation:
given data
P = 300 - 2QD Â
P = 100 + 3QS Â
to find out
sum of the consumer and producer surplus
solution
we first equating both  as equilibrium at QD = QS
so
300 - 2Q = 100 + 3Q
solve we get
Q = 40
so P will be
P = 3 00 - 2 × 40
P = 220
Consumer surplus  area above price and below demand  so
Consumer surplus  = 0.5 × (300 - 220) ×  40
Consumer surplus  = 1600
and
Producer surplus  area above supply curve and below price so
Producer surplus = 0.5 × (220 - 100) × 40
Producer surplus = 2400 Â
so Total surplus will be
Total surplus = Consumer surplus + Producer surplus Â
Total surplus = 1600 + 2400
Total surplus = Â 4000
so correct option is D. $4000