Two Firms Can Choose from Five Different Technologies to Reduce

Two firms can choose from five different technologies to reduce their pollution: A,B,C,D and E.The amount of pollution emitted by each technology and the cost of the technologies are shown in the table.Both firms have adopted technology A and currently emit 4 tons apiece.The government is considering two plans to reduce pollution: a 50% reduction by both firms or selling pollution permits.One permit entitles the owner to emit one ton of pollution.Without a permit,no pollution can be emitted.
$\begin{array}{lccccc} & \text { A: } & \text { B: } & \text { C: } & \text { D: } & \text { E: } \\& 4 \text { tons } & 3 \text { tons } & 2 \text { tons } & 1 \text { ton } & \text { no pollution } \\\text { Industrio } & \$ 350 & \$ 400 & \$ 500 & \$ 700 & \$ 1000 \\\text { Capitalista } & \$ 225 & \$ 250 & \$ 290 & \$ 400 & \$ 600\end{array}$
If the government decided to use permits instead of regulation,in order to reduce pollution by 50% it would need to sell _____ permits.

A) 4
B) 2
C) 3
D) 5