Westhaven Company Has a Warehousing Unit Which Operates as a Cost

Westhaven Company has a warehousing unit which operates as a cost center. They prepare monthly performance reports.
The report for February is shown here:
$\begin{array}{|l|r|r|r|r|r|r|}\hline \text { Cost Center } & & \text { Flexible } & \text { Flexible Budget } \\\hline \text { Performance Report } & \text { Actual } & \text { Budget } & \text { Variance } & \text { U/F } & \% \text { variance } & \text { U/F } \\\hline \text { Salary \& benefits } & \$ 119,000 & \$ 120,000 & \$ 1,000 & F & 0.8 \% & F \\\hline \text { Rent expense } & 94,500 & 90,000 & 4,500 & U & 5.0 \% & U \\\hline \text { Depreciation expense } & 23,200 & 24,000 & 800 & F & 3.3 \% & \text { F } \\\hline \text { Depreciation expense } & 23,200 & 24,000 & 800 & F & 3.3 \% & \text { F } \\\hline \text { Supply expense } & 11,890 & 12,000 & 110 & \text { F } & 0.9 \% & \text { F } \\\hline \text { Other expense } & 8,120 & 8,000 & 120 & \mathrm{U} & 1.5 \% & \mathrm{U} \\\hline& \$ 256,710 & \$ 254,000 & \$ 2,710 & \mathrm{U} & 1.1 \% & \mathrm{U} \\\hline\end{array}$

Westhaven uses the management by exception approach. On which of the following variances would the company focus first for investigation and explanation?

A) Supply expense
B) Rent expense
C) Other expense
D) Depreciation expense