Stocks A$,$ B$,$ C$,$ and D have returns of $10\%,20\%,30\%,$ and $40\%,$ respectively. What is their variance?

Question $15$ options:

a$)$

$66\mathrm{.}67\%$

b$)$

$166\mathrm{.}67\%$

c$)$

$4\mathrm{.}08\%$

d$)$

$2\mathrm{.}15\%$