Sheridan Corporation purchased a patent for $124500 on September 1, 2016. It had a useful life of 10 years. On January 1, 2018, Sheridan spent $26000 to successfully defend the patent in a lawsuit. Sheridan feels that as of that date, the remaining useful life is 5 years. What amount should be reported for patent amortization expense for 2018?

$25120.

$27610.

$26780.

$21580.