Sarah is trying to better understand her company's overhead costs to respond to an e$-$mail from her supervisor. She quickly gathered

information from the last $3$ months regarding production counts and key overhead costs, as follows.

$($a$)$

Based on just the information provided above, help Sarah classify each of the three costs by behavior: variable, fixed, or mixed.

Utility cost

Indirect material cost

Fixed cost

Mixed cost

Variable cost

Depreciation cost