i think the answer is D, but not sure

13.A corporation is selling an existing asset for $21,000. The asset, when purchased, cost $10,000, was being depreciated under MACRS using a five-year recovery period, and has been depreciated for four years. If the assumed tax rate is 21 percent, find the tax effect of this transaction. a. $8,400 tax benefit b. $8,400 tax liability $4,053 tax benefit $4,053 tax liability