The y-intercept is a) The variable cost.
What is the y-intercept?
In the question, we are told that the y-intercept is the overhead cost Monica pays each month. In the question, we are told that Monica pays $2500 per head for her overhead costs to run the studio.
Overhead costs are the changing manufacturing costs involved in running a business. So, in the case of Monica, the amount of $2500 is a variable cost or overhead cost involved in running the business. Option A is thus correct. These costs include the indirect material cost, the indirect labor costs and the indirect expenses costs.