Final answer:
Composite or group depreciation is described by calculating a straight-line rate based on the total annual depreciation expense over the total cost of the group's assets.
Step-by-step explanation:
The statement that accurately describes composite or group depreciation is C. With composite or group depreciation, a straight-line rate is computed by dividing the total of the annual depreciation expense for all assets in the group by the total cost of the assets. This method allows for a more straightforward calculation where assets with different lives are depreciated as a single group or pool without allocating the cost to individual assets. The annual depreciation expense is applied uniformly, which offers convenience and simplifies accounting practices.