The correct answer is A. The boat rental was worth the additional fish caught, regardless of how little fish we left behind.
Explanation:
The self-interest concept in the economy proposes individual interests prevail over general society interests. This means consumers make decisions only based on their concerns. This can be seen in "The boat rental was worth the additional fish caught" because in this case, the consumer is only thinking about the money he/she earns through the boat rental, which is an individual interest. Also by stating "regardless of how little fish we left behind" the consumer shows he/she is not interested in the ecosystem or whether there is going to be fish in the future, and therefore the consumer is not thinking about the general societal interests.