A company paid \(\$ 900,000\) for a building and was amortizing it by the straight-line method over a 40 -year life, with estimated residual value of \(\$ 60,000\). After 10 years it became evident that the building's remaining useful life would be 40 years with a residual value of \(\$ 50,000\). Amortization for the 12th year is

a. \(\$ 16,000\)

b. \(\$ 17,250\)

c. \(\$ 21,000\)

d. \(\$ 28,000\)