Answer:
Dec 31 Dr Service Revenue 13,000
Cr Income Summary 13,000 
Dec 31 Dr Income Summary 10,000
Cr Wages Expense 8,400 
Cr Rent Expense 1,600 
Dec 31 Dr Income Summary 3,000
(13,000-10,000)
Cr Retained Earnings 3,000
Dec 31 Dr Retained Earnings 800 
Cr Dividends 800 
Explanation:
Preparation of its December 31 closing entries.
Dec 31 Dr Service Revenue 13,000
Cr Income Summary 13,000 
(Being to close revenue account)
Dec 31 Dr Income Summary 10,000
(8,400+1,600)
Cr Wages Expense 8,400 
Cr Rent Expense 1,600 
(Being to close expense account)
Dec 31 Dr Income Summary 3,000
(13,000-10,000)
Cr Retained Earnings 3,000
(Being to close net income/loss)
Dec 31 Dr Retained Earnings 800 
Cr Dividends 800 
(Being to close dividends)