a$.$ Use Trace Dependents arrows to determine whether the #VALUE! error in cell D$12$ is causing the other errors in the worksheet.

b$.$ Use Trace Precedents arrows to find the source of the error in cell D$12.$

c$.$ Correct the error so that the formula in cell D$12$ calculates the cumulative straight$-$line depreciation of the medical van by adding the Cumulative depreciation value in Year $1$ to the Annual depreciation value in Year $2.$