Final answer:
Opportunity cost is the value of the next best alternative that one must give up to obtain what he or she desires. In the context of a seller's opportunity cost, it refers to the value of everything she must give up to produce a good.
Step-by-step explanation:
Opportunity cost is the value of the next best alternative that one must give up to obtain what he or she desires. In the context of a seller's opportunity cost, it refers to the value of everything she must give up to produce a good. This includes not only the out-of-pocket expenses to produce the good but also the value of her time and any other resources used in the production process.
For example, let's say a seller has the opportunity to produce either shirts or pants. If she chooses to produce shirts, her opportunity cost would be the profit she could have made from producing pants. This would include not only the material costs and labor costs of producing shirts, but also the potential profit from selling the pants.
Therefore, the correct answer is a. value of everything she must give up to produce a good.