Explanation:

- Option 1: Perfect Competition

- Many firms compete in a market.

- No single firm influences the market price.

- Products are identical and easily substitutable.

- Option 2: Monopolistic Competition

- Many firms with differentiated products.

- Some control over prices due to product uniqueness.

- Consumer choice is driven by variety and branding.

- Option 3: Duopoly

- Only two major firms dominate the market.

- Each firm considers the other's reactions in their decision-making.

- Option 4: Monopoly

- ?? The firm and the industry are one and the same.

- Only one firm provides a unique product or service.

- Complete control over market price and output.