Final answer:
Vacant land cannot be depreciated because it does not deteriorate over time and has an unlimited useful life, unlike structures that can be depreciated due to wear and tear.
Step-by-step explanation:
The investment that cannot be depreciated is C) 100 acres of vacant land. Depreciation is an accounting method used to allocate the cost of a tangible asset over its useful life. In the context of real estate, buildings such as commercial buildings, single-family homes, and shopping malls can be depreciated because they are structures that wear out, decay, get used up, become obsolete, or lose value from natural causes over time.
Vacant land, however, does not wear out, become obsolete, or get used up, and the IRS does not allow for land to be depreciated. This is because land is considered to have an unlimited useful life compared to structures that are subject to wear and tear. Therefore, the correct answer is vacant land, as it is the type of investment that does not decrease in utility over time and cannot be depreciated for tax purposes.