French Co Ltd Has a Machine with the Following Characteristics

French Co Ltd has a machine with the following characteristics: A more technically advanced machine is expected to be available in 8 years.
It is expected to continue operating efficiently for the next 13 years.
The product that the machine is used to produce is expected to have a viable market for the next 6 years.
What is the period of time that should be used as the useful life of the asset for the purpose of calculating depreciation?

A) 8 years.
B) 6 years.
C) 13 years.
D) 9 years.
E) None of the given answers.