Barber, Inc., followed the practice of depreciating its building on a straight-line basis. A building was purchased in 2011 and had an estimated useful life of 25 years and a residual value of \(\$ 20,000\). The company's depreciation expense for 2011 was \(\$ 20,000\) on the building. What was the original cost of the building?

a. \(\$ 480,000\)

b. \(\$ 500,000\)

c. \(\$ 520,000\)

d. Cannot be determined from the information given.