Answer
The box with $0.008$ inch diameter is the green box.
Work Step by Step
In order to find out which box has a $\frac{1}{125}$ inch diameter, we need to convert the fraction to a decimal. We do this by dividing $1$ by $125$:
$~~~~~~~0.008$
$125\overline{)1.000}$
$~~~~~~~~\underline{1~000}$
$~~~~~~~~~~~~~~~0$
We see from the graphic that the box with $0.008$ inch diameter is the green box.