A machine with an original cost of $6,000, an expected useful life of 5 years, and salvage value of $500, is depreciated by the straight line method. The machine was purchased on January 1, 2015. On July 1, 2017, the machine is sold for $2,500. The entry to record the sale will include? (Please provide an explanation of your response)

A) a loss of $500

B) a gain of $500

C) a loss of $750

D) a gain of $750