The asset served part of the final year, so that expense belongs to the period before the comparison is made.
This ignores accumulated depreciation entirely and would report a loss on almost every disposal.
The months of service in the final year would go unrecorded, overstating the carrying amount and understating the gain.
The computation is right and the presentation is not. A disposal is peripheral for most entities and is reported net, below the operating subtotal.
Answer: a
Choice a. Update depreciation first, compare with proceeds, and present the result below operating income.