Final answer:
Nils can potentially deduct the full $4,500 for the business computer using the special depreciation allowance on his California return, as it's assumed to conform with the federal treatment allowing 100% bonus depreciation for such business assets.
Step-by-step explanation:
The maximum amount Nils can deduct on his California return using the special depreciation allowance for the business computer purchased at $4,500 is $4,500. This is because, generally, the federal tax law allows for 100% bonus depreciation on qualified business property, which includes computers used exclusively for business purposes. Since the question is referring to California tax law, it is assumed to conform to the federal treatment unless specified otherwise. Additionally, Nils’ business income is enough to fully absorb the deduction.
Since Nils purchased a new computer for $4,500 and uses it exclusively for business, he can deduct the full cost of the computer on his California return using the special depreciation allowance. Therefore, the maximum amount he can deduct is $4,500.