A machine has an estimated 10 percent salvage value at the end of its 5-year useful life. Under which of the following depreciation methods would the book value of the asset be zero at the end of its useful life?

	A.	Double-declining-balance method.
	B.	Units of production method.
	C.	Straight-line method.
	D.	All of the above.
	E.	None of the above.