Answer: a. Higher than 100 units , price lower than $5 and Mr = price
Explanation:
Firms competing in perfect market conditions are Price Takers, the produce quantity at the level where Marginal Revenue equals Marginal cost. Since firms are price takers their Marginal Revenue is the Market Price P. They can only increase quantity if they want to earn more profit, Therefore Price = Marginal Revenue = Marginal Cost.
The Quantity will increase and the price will be lower than $5. Price = Marginal Revenue = Marginal cost. The Price will be $4