Suds and Spirits purchased a customer list from a nearby gourmet grocery for $20,000 on January 1, 2017. The expected service life was 5 years with an expected residual value of $2,000. Since the list would be most valuable (most current) in the first few years, the company elected to use double-declining balance method of amortizing the cost. By December 31, 2019, it was clear that the customers on the list were more stable than Subs and Spirits expected. The owners believed that the customer list would have a total useful life of 10 years with no residual value. The amortization method was switched to straight-line. What was amortization expense for 2020?

a. $841

b. $617

c. $432

d. $695