The correct answer is C. Telephone expenses.
Semi-variable costs are costs that are partly fixed and partly variable. They are also known as mixed costs or semi-fixed costs. Semi-variable costs change in proportion to changes in output, but not in direct proportion. This means that they have a fixed component and a variable component. The fixed component remains the same regardless of the level of output, while the variable component changes in direct proportion to changes in output.
Telephone expenses are an example of semi-variable costs because they have both a fixed and a variable component. The fixed component is the cost of the phone line and the monthly service charge. The variable component is the cost of long-distance calls and other usage charges. The total cost of telephone expenses will increase as the number of long-distance calls and other usage increases.
Salary is an example of a fixed cost. A salary is a fixed amount of money that is paid to an employee on a regular basis, regardless of the number of hours worked. Tax is an example of a variable cost. Taxes are levied on businesses and individuals based on their income or profits. The amount of tax that is paid will vary depending on the level of income or profits. Office expenses are an example of a mixed cost. Office expenses include items such as rent, utilities, and office supplies. The amount of office expenses will vary depending on the size of the office and the number of employees.
In conclusion, the correct answer is C. Telephone expenses.