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:

The stock of grommet corporation, a u.s. company, is publicly traded, with no single shareholder owning more than 5 percent of its outstanding stock. grommet owns 95 percent of the outstanding stock of staple inc., also a u.s. company. staple owns 100 percent of the outstanding stock of clip corporation, a canadian company. grommet and clip each own 50 percent of the outstanding stock of fastener inc., a u.s. company. grommet and staple each own 50 percent of the outstanding stock of binder corporation, a u.s. company. which of these corporations form an affiliated group eligible to file a consolidated tax return?