Final answer:
Group depreciation is a method where similar assets are collectively depreciated as one unit, simplifying accounting processes while considering the useful life of the assets. Correct option is B.
Step-by-step explanation:
Composite or group depreciation is a depreciation system whereby B) A group of similar assets is treated as a single unit for depreciation. This method simplifies the accounting process by allowing for a single depreciation rate to be applied to a group of assets, rather than determining and tracking the depreciation of each asset individually. However, it's important to note that even though the assets are grouped together, the useful life of each asset within the composite group is still taken into consideration when calculating depreciation.