Following Is an Extract of Account Balances of Wilson Mowing

Following is an extract of account balances of Wilson Mowing Service as at 31 December of the first year of operation:
$$\begin{array} { | l | l | } \hline \text { Accounts receivable } & \$ 4000 \\\hline \text { Accounts payable } & 7000 \\\hline \text { Salary expense } & 5000 \\\hline \text { Repairs expense } & 700 \\\hline \text { Truck } & 11,000 \\\hline \text { Equipment } & 9000 \\\hline \text { Loans payable } &8400 \\\hline \text { Cash } & 7000 \\\hline \text { Supplies expense } & 1000 \\\hline \text { Service revenue } & 32,000 \\\hline \text { Petrol expense } & 2900 \\\hline \text { Salary payable } & 300 \\\hline\end{array}$$
At the end of the year,what is the amount of total assets?

A) $27,000
B) $20,000
C) $31,000
D) $15,000