Answer:
b. debit Machinery and Accumulated Depreciation; credit Machinery, Cash, and Gain on Disposal
Explanation:
When machinery exchange and its value is greater than the book value so the journal entry is recorded which is shown below:
Machinery A/c Dr XXXXX
Accumulated depreciation A/c Dr XXXXX
To Machinery A/c XXXXX
To Cash A/c XXXXX
To Gain on disposal A/c XXXXX
(Being the exchange is recorded)
Hence the most appropriate option is b.