Answer:
Consider the following explanation
Explanation:
Some goods are too dangerous or important to let "just anyone " produce them, example, railway or some defence equipment. (A),
Monopolies reduce the total cost when they are very large fixed cost in production. that is when they are achieving economies of scale. "d".
An providing some monopoly power ensure they are inventing and that make the monopoly important that is why the government protects them through patents. (B).