Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
-A bag contains 9 red marbles, 3 blue marbles, and 7 green marbles. If one marble is selected at random, determine the probability that it is blue.

A) $\frac { 3 } { 19 }$
B) $\frac { 1 } { 4 }$
C) $\frac { 9 } { 19 }$
D) $\frac { 7 } { 19 }$