On January 1, 2013, F Corp

On January 1, 2013, F Corp. issued 2,000 of its 10%, $1,000 bonds for $2,080,000. These bonds were to mature on January 1, 2023, but were callable at 101 any time after December 31, 2016. Interest was payable semiannually on July 1 and January 1. On July 1, 2018, F called all of the bonds and retired them. The bond premium was amortized on a straight-line basis. Before income taxes, F Corp.'s gain or loss in 2018 on this early extinguishment of debt was:

A) $16,000 gain.
B) $20,000 loss.
C) $24,000 gain.
D) $60,000 gain.