Which of the following is considered a part of the cost of a product?

Unit cost is considered a part of the cost of a product because it directly relates to the expenses incurred in producing a single unit of that product. This includes expenses like materials, labor, and overhead costs associated specifically with the production process. Understanding the unit cost helps businesses in pricing their products correctly, analyzing profitability, and managing overall expenses effectively.

While staff salaries, marketing expenses, and research and development costs contribute to the overall finances of a company, they are not directly tied to the cost of producing a specific product in the same way that unit cost is. Staff salaries can be part of operational costs, marketing expenses are related to promoting the product, and research and development costs involve innovation and product improvement, but they do not represent the direct cost involved in manufacturing each unit sold.