On July 1 of the Current Year, a Company Purchased

On July 1 of the current year, a company purchased and placed in service a machine with a cost of $240,000. The company estimated the machine's useful life to be four years or 60,000 units of output with an estimated salvage value of $60,000. During the current year, 15,000 units were produced.
Prepare the necessary December 31 adjusting journal entry to record depreciation for the current year assuming the company uses:
A) The straight-line method of depreciation
B) The units-of-production method of depreciation
C) The double-declining balance method of depreciation