Option 1 -> Total cost refers to the sum of all costs incurred, not the cost of foregone alternatives.
Option 2 -> Marginal cost is the cost of producing one additional unit, not applicable to job selection.
Option 3 -> Differential cost is the difference in costs between alternatives, but doesn't capture the concept of foregone benefits.
Option 4 -> Opportunity cost represents the value of the next best alternative that must be sacrificed when making a choice.
Hence, Opportunity cost -> When an individual selects the best job among three alternatives, the value of the next best job option that is foregone represents the opportunity cost. This is a fundamental economic concept that measures the cost of a choice in terms of the benefit of the next best alternative sacrificed. In this case, by choosing the best job, the individual gives up the benefits (salary, perks, growth, etc.) of the second-best job option, which becomes their opportunity cost -> correct