To book 1 year's depreciation on a machine which costs $30,000 and has a 10-year usable life, you would enter the following:

A) Debit: Depreciation Expense $3000; Credit: Machine $3000

B) Debit: Accumulated Depreciation $3000; Credit: Cash $3000

C) Debit: Depreciation Expense $3000; Credit: Accumulated Deprecation $3000

D) Debit: Accumulated Deprecation $3000; Credit: Deprecation Expense $3000

... Using the previous entry, at the end of year 3, calculate what the balance in the Accumulated Depreciation account on the machine would be, and give the net book value, or carry value of the machine on the balance sheet.