Find the Indicated Probability If One of the 255 Subjects Is Randomly Selected, Find

Find the indicated probability. Express your answer as a simplified fraction unless otherwise noted.
-The table below shows the soft drinks preferences of people in three age groups.
$$\begin{array} { r | c c c } & \text { cola } & \text { root beer } & \text { lemon-lime } \\\hline \text { under 21 years of age } & 40 & 25 & 20 \\\text { between 21 and 40 } & 35 & 20 & 30 \\\text { over 40 years of age } & 20 & 30 & 35\end{array}$$
If one of the 255 subjects is randomly selected, find the probability that the person is over 40 years of age given that they drink root beer.

A) $\frac { 5 } { 17 }$

B) $\frac { 6 } { 17 }$

C) $\frac { 2 } { 5 }$

D) None of the above is correct.