Jennings Advertising Inc $\begin{array}{lr}\text {Equipment }&\$500,000\\\text {Less: Accumulated depreciation- equipment }&\$135,000\\\end{array}$

Jennings Advertising Inc. reported the following in its December 31, 2018, balance sheet: $\begin{array}{lr}\text {Equipment }&\$500,000\\\text {Less: Accumulated depreciation- equipment }&\$135,000\\\end{array}$
In a disclosure note, Jennings indicates that it uses straight-line depreciation over 10 years and estimates salvage value at 10% of cost. What is the average age of the equipment owned by Jennings?

A) 2.7 years.
B) 3 years.
C) 7 years.
D) 7.3 years.