The value of x where x : 21/3 :: 21 : 50 is -

Answer: Option C

$$\begin{array}{rl}& =x:2\frac{1}{3}::21:50\\ & \Rightarrow 50x=\frac{7}{3}\times 21\\ & \Rightarrow 50x=49\\ & \Rightarrow x=\frac{49}{50}\end{array}$$