The depreciation method that is not based on the passage of time is the Units-of-production method (Option C).
Here's why:
1. **Straight-line method:** This method depreciates assets evenly over their useful life. It is based on time, allocating an equal amount of depreciation expense for each period of the asset's useful life.
2. **Declining-balance method:** This method accelerates depreciation, with higher depreciation expenses in the early years and decreasing amounts in later years. It is also based on time as it applies a fixed percentage to the remaining book value of the asset each year.
3. **Parallel method:** This method is not a standard depreciation method and is not commonly used in accounting. It is not specifically based on time but rather operates in parallel with another method for comparison purposes.
4. **Units-of-production method:** This depreciation method is based on the actual usage of the asset rather than the passage of time. Depreciation is calculated based on the number of units produced or the hours the asset is expected to be used.
Therefore, the correct answer to the question is Option C: Units-of-production method.
