If random variable $X:$ waiting time in minutes for bus and probability distribution function of $X:$ is given by



$f\left(x\right)=\left\{\begin{array}{cc}\frac{1}{5},& 0\le x\le 5\\ 0,& \mathrm{o}\mathrm{t}\mathrm{h}\mathrm{e}\mathrm{r}\mathrm{w}\mathrm{i}\mathrm{s}\mathrm{e}\end{array}\right.$



Then probability of waiting time not more than $4$ minutes is = _______

• A

  $0.3$
• Correct answer
  B

  $0.8$
• C

  $0.2$
• D

  $0.5$

Hence, the correct answer is option: 'B'.