Following Is a List of Account Balances of Wilson Mowing

Following is a list of account balances of Wilson Mowing Services as of December 31 of the first year of operation:
$$\begin{array} { | l | r | } \hline \text { Accounts receivable } & \$ 5,000 \\\hline \text { Accounts payable } & 4,000 \\\hline \text { Salary expense } & 5,000 \\\hline \text { Repairs expense } & 1,000 \\\hline \text { Truck } & 10,000 \\\hline \text { Equipment } & 8,000 \\\hline \text { Notes payable } & 8,200 \\\hline \text { Cash } & 7,500 \\\hline \text { Supplies expense } & 1,600 \\\hline \text { Service revenue } & 32,000 \\\hline \text { Gasoline expense } & 3,800 \\\hline \text { Salary payable } & 200 \\\hline\end{array}$$ What is the amount of total liabilities at the end of the year?

A) $12,400
B) $24,100
C) $21,200
D) $12,200