please tell me to choose which one

Exercise 10-18 Larkspur Company purchased an electric wax melter on April 30, 2017, by trading purchase. its old gas model and paying the balance in cash. The following data relate to the List price of new melter $18,644 Cash paid 11,800 Cost of old melter (5-year life, $826 salvage value) 13,216 Accumulated Depreciation-old melter (straight-line) 7,434 Secondhand fair value of old melter 6,136 Prepare the journal entries necessary to record this exchange, assuming that the exchange (a) has commercial substance, and (b) lacks commercial substance. Larkspur's fiscal year ends on December 31, and depreciation has been recorded through December 31, 2016. (Credit account titles are automatically indented when amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter for the amounts.) No. Account Titles and Explanation Debit Credit (a) Exchange has commercial substance: Depreciation Expense Accumulated Depreciation-Building (To record current depreciation.) Gain on Disposal of (To record exchange of the equipment.) (b) Exchange lacks commercial substance: (To record current depreciation.) (To record exchange of the equipment.) Gain on Disposal Gain on Disposal of Buildings Gain on Disposal of Equipment |(b) Gain on Disposal of Machinery Gain on Disposal of Trucks