Fixed Costs
Fixed costs are costs that do not change with the level of production or sales. These costs remain constant regardless of the volume of output. They are incurred even if no production or sales occur. Examples of fixed costs include rent, salaries, insurance, and depreciation.

Variable Costs
Variable costs, on the other hand, are costs that change in direct proportion to the level of production or sales. These costs fluctuate with changes in the level of activity. Examples of variable costs include direct materials, direct labor, and sales commissions.

Prime Costs
Prime costs refer to the direct costs involved in the production of goods or services. They include direct materials and direct labor costs. Prime costs exclude indirect costs such as overhead expenses.

Explanation
Out of the given options, fixed costs are the only costs that can never be zero. Fixed costs are incurred regardless of the level of production or sales. They are necessary expenses that a business must bear to maintain its operations, even if it is not generating any revenue.

Variable costs can be zero if there is no production or sales activity. For example, if a manufacturing plant is shut down, there will be no direct material or direct labor costs incurred, resulting in zero variable costs.

Similarly, prime costs can be zero if there is no production activity. If a business is not producing any goods or services, there will be no direct material or direct labor costs incurred, resulting in zero prime costs.

However, fixed costs cannot be zero as they are ongoing expenses that must be paid regardless of the level of production or sales. These costs are essential for the business to function and maintain its operations, such as paying rent, salaries, and insurance premiums.