Answer: At the prevailing market price.

In highly competitive markets, firms typically act as price takers, meaning the price of their output is determined by market forces of supply and demand rather than individual firm decisions. Natural resources companies, such as those in oil and gas, operate in such markets where products are largely undifferentiated, barriers to entry are low, and substitutes are readily available. Consequently, these firms sell their output at the prevailing market price. Options B and C are incorrect because they imply pricing power or unilateral pricing decisions, which are not characteristic of competitive markets.

Author: LeetQuiz Editorial Team