During 2012, Traco Machine Company spent $176,000 on R&D costs for an invention. This invention was patented on January 2, 2013, at a nominal cost that was expensed in 2013. The patent had a legal life of 20 years and an estimated useful life of 8 years. In January 2017, Traco paid $16,000 for legal fees in a successful defense of the patent. Amortization for 2017 should be:
a. $1,000
b. $26,000
c. $0
d. $4,000