What Would Be the Account Balance in the Revenue Ledger

What would be the account balance in the revenue ledger account after the following transactions?
$$\begin{array} { | l | r | } \hline \text { Performed services and left a bill } & \$ 4,200 \\\hline \text { Performed services and collected immediately } & \$ 3,500 \\\hline \text { Performed services and billed customer } & \$ 2,200 \\\hline \text { Performed services on account } & \$ 6,000 \\\hline \text { Received partial payment on account } & \$ 1,500 \\\hline\end{array}$$

A) $17,400
B) $10,900
C) $14,400
D) $9,000
E) $15,900