Explanation:

- In perfect competition, a firm cannot determine the price it charges for its output.

- Prices are determined by the market as a whole, due to many firms selling identical products.

- Each firm is a price taker, meaning it accepts the prevailing market price.

- Option 2: Obtains price - This is correct. Firms take the market price as given.

- Option 1: Determines price - Incorrect; firms do not control the price.

- Option 3: Both (a) and (b) - Incorrect; firms only obtain the price.

- Option 4: None of these - Incorrect; the correct scenario is described in Option 2.