Use This Adjusted Trial Balance to Answer the Following Question

Use this adjusted trial balance to answer the following question. $\begin{array}{c}\text {Dan's Marina}\\\text {Adjusted Trial Balance}\\\text {December 31, 2010}\\\begin{array}{|l|r|r|}\hline \text { Cash } & \$ 2,500 \\\text { Accounts Receivable } & 3,500 \\\text { Supplies } & 1,500 \\\text { Prepaid Insurance } & 2,500 \\\text { Dock } & 12,000\\\text { Accumulated Depreciation-Dock } & & \$ 3,000 \\\text { Accounts Payable } && 6,000 \\\text { Common Stock } && 10,000 \\\text { Dividends } & 4,000 & \\\text { Boat Rentals } & & 17,000\\\text { Depreciation Expense-Dock } & 1,000 & \\\text { Wages Expense } & 6,500 & \\\text { Insurance Expense } & 2,000 & \\\text { Income Taxes Expense } & 500 \\ & \$ 36,000 & \$ 36,000 \\\hline\end{array}\end{array}$

The entry to close Income Summary includes a

A) credit to Common Stock for $8,000.
B) credit to Income Summary for $12,000.
C) debit to Income Summary for $7,000.
D) debit to Retained Earnings for $16,000.