Costs can be classified according to different criteria and for various purposes. Which claim about this is correct?

- When costs are classified by primary types, they are divided into fixed and variable costs; in this case, wages are labor costs, they are classified as variable costs.

- When we classify costs by primary types, we are interested in the nature of business resources causing the cost; in this case, depreciation is the cost of the material.

- When we classify costs into fixed and variable, we are interested in how costs change as the volume of business activity changes; in this case, depreciation is the cost of material, it is classified as variable cost.

- When we classify costs into fixed and variable, we are interested in the nature of business resources causing the cost; in this case, depreciation is the cost of property, plant, and equipment.

- When costs are classified by primary types, we are interested in the nature of business resources causing the cost; in this case, depreciation is the cost of property, plant, and equipment.