A monopolistically competitive market A. is not imperfectly competitive. B. is imperfectly competitive, but not all imperfectly competitive markets are monopolistically competitive. C. is imperfectly competitive, whereas an oligopolistic market is not imperfectly competitive.

b. is imperfectly competitive, but not all imperfectly competitive markets are monopolistically competitive.

Explanation:

A market will be considered as 'Imperfectly competitive" if either of these criteria are met:

1. There are barriers to enter the market

2. the products that they offer have a different variant and qualities.

3. Consumers have limited information about the product.

Monopolistic ally competitive market is considered as imperfectly competitive since it checks out all criteria.

But in general, free market economy tend to have imperfect competition. You can see it in united states market. Technically, there is almost no monopoly in the market. but the products that offered have different variance and there are capital barriers for new business to thrive.