When a consumer compares the price of a good to the value of that good, he or she is really comparing: a. the value of the good to its opportunity cost.
b. the price of the good to the value of other substitute goods.
c. the price of other substitute goods.
d. the value of the good to the costs associated with producing the good.

a. the value of the good to its opportunity cost.

Explanation:

In Economics, Opportunity cost also known as the alternative forgone, can be defined as the value, profit or benefits given up by an individual or organization in order to choose or acquire something deemed significant at the time.

Simply stated, it is the cost of not enjoying the benefits, profits or value associated with the alternative forgone or best alternative choice available. Thus, the opportunity cost of a choice is the benefits that could be derived in from another choice using the same amount of resources.

For instance, if you decide to invest resources such as money in a food business (restaurant), your opportunity cost would be the profits you could have earned if you had invest the same amount of resources in a salon business or any other business as the case may be.

Hence, when a consumer compares the price of a good to the value of that good, he or she is really comparing the value of the good to its opportunity cost because the opportunity cost of a choice refers to the value of the alternative forgone or opportunities lost.