Butte Sold a Machine to a Machine Dealer for $50,000

Butte sold a machine to a machine dealer for $50,000. Butte bought the machine for $55,000 several years ago and has claimed $12,500 of depreciation expense on the machine. What is the amount and character of Butte's gain or loss?

A) $7,500 §1231 loss.
B) $5,000 §1231 loss.
C) $7,500 ordinary gain.
D) $7,500 capital gain.
E) None of these.