At a computer$-$consulting firm, the number of new clients that they have obtained each month has ranged from $0$ to $6.$ The number of new clients has the probability distribution that is shown below.

Determine the variance of the new clients per month.

$\backslash$table$[[$#$,$of Clients Probability$],[0,0\mathrm{.}05],[1,0\mathrm{.}10],[2,0\mathrm{.}15],[3,0\mathrm{.}35],[4,0\mathrm{.}20],[5,0\mathrm{.}10],[6,0\mathrm{.}05]]$

$2\mathrm{.}0475$

$1\mathrm{.}431$

none of the answers is correct

$21$

$3\mathrm{.}05$