The following costs are labeled fixed or variable according to a typical designation in accounting. Identify the circumstances under which any of these costs would behave in a manner opposite to that listed:

a. Direct labor-variable.

b. Equipment depreciation-fixed.

c. Utilities (with a minimum charge)-variable.

d. Supervisory salaries —fixed.

e. Indirect materials purchased in given sizes that become spoiled within a few days—variable.