On January 1, 2015 Sky Company purchased a patent for $94,000. The company originally expected to use the patent for eight years and then sell it for $5,000. During 2021, management adjusted the total useful life of the patent to thirteen years and the residual value to $1,000. The company amortizes all patents using straight-line.

The 2021 annual amount of amortization expense for the patent is A. 6,229 B. 3,750 C. 3,893 D. 2,016