A box contains 5 red balls, 3 blue balls, and 2 green balls. One ball is drawn at random from the box.
What is the probability that the drawn ball is blue?
\noindent(A) $\dfrac{1}{10}$\\
(B) $\dfrac{1}{5}$\\
(C) $\dfrac{3}{10}$\\
(D) $\dfrac{2}{5}$\\
(E) $\dfrac{1}{2}$