The probability distribution of a random variable X is given below. Then, the standard deviation of X is

$X=x_i$	2	3	5	7	12
$\mathrm{P}\left(\mathrm{X}=x_i\right)$	3k	k	k	2k	k

• A

  5
• B

  11
• Correct answer
  C

  $\sqrt{11}$
• D

  $\sqrt{5}$

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