Equipment with a cost of $160,000, an estimated residual value of $10,000, and an estimated life of 4 years, was purchased on April 1, 2018. Year end is December 31, 2018. If the straight-line method is used the depreciation expense for 2018 is : Select one: O a $37,500 Ob $30,000 Oc$28,125 Od $40,000