Incremental costs considered in differential costing are primarily:

Incremental costs in differential costing specifically refer to the additional costs that are associated with producing a particular product or service beyond what is already incurred. This concept emphasizes the financial implications of choosing one alternative over another, focusing on costs that specifically change as a result of that decision.

When considering incremental costs, only those that are directly related to the decision at hand are taken into account. This is essential in differential costing, as it helps in evaluating the potential profit or loss from different courses of action. By isolating these costs, organizations can make informed decisions that reflect the true financial impact of moving forward with a specific product line or service offering.

While fixed costs that do not vary or general administrative costs might impact the overall profitability of a business, they do not factor into the specific evaluation of different choices since they remain unchanged regardless of the decision made. Overhead expenses also generally do not change with the addition or deletion of a product, making them less relevant in the context of incremental costing for decision-making purposes. Thus, the focus on costs that are uniquely tied to specific products or services is what makes option B the correct choice.