Question

the cost-benefit model used by economists is
unrealistic because it is too detailed and specific to apply to a variety of situations.
unrealistic because everyone can think of times when he or she violated the principle.
useful because everyone follows it all of the time
useful because most people follow it most of the time.
used primarily by accountants and business managers.

Explanation:

The cost - benefit model in economics is a tool to analyze decisions. It's not unrealistic due to detail or personal violations. People don't follow it all the time, so the option saying everyone follows it is wrong. It's not mainly for accountants and managers. The correct reasoning is that it's useful as most people follow it most of the time, as it provides a framework for decision - making that aligns with how people generally make choices in many situations.

Answer:

D. useful because most people follow it most of the time.