Explain the difference between variable costs and fixed costs O A. O B O c. Variable costs increase proportionally with changes in the activity level of some variable and fixed costs are costs that vary with the amount of capacity used. Variable costs increase proportionally with changes in the activity level of some variable and fixed costs are costs that in the short run do not vary with a specified activity. variable costs decrease during the manufacturing state of a product and fixed costs are costs that vary with the amount of capacity used. Vanable costs decrease during the manufacturing state of a product and fixed costs are costs that in the short run do not vary with a specified activity O D