Please help me solve this general accounting question using the right accounting principles.

On December 31, Ace Fitness Centre decided to sell one of its treadmills. The initial cost of the equipment was $150,000, and the accumulated depreciation recorded on the equipment was $120,000. Depreciation has been recorded through the end of the year. The equipment was sold for $25,000. What is the amount of the gain or loss on this transaction? a. Gain of $5,000 b. Loss of $5,000 c. No gain or loss d. Cannot be determined