Hepburn Company bought a copyright for $90,000 on January 1, 2015, at which time the copyright had an estimated useful life of 15 years. On January 5, 2018, the company determined that the copyright would expire at the end of 2021. How much should Hepburn record as amortization expense for this copyright for 2018?

a.$14,400.

b.$7,200.

c.$18,000.

d.$12,000.