You have been given this probability distribution for the holding$-$period return for KMP stock:

Stock of the Economy Probability HPR

Boom $0\mathrm{.}3018\%$

Normal growth $0\mathrm{.}5012\%$

Recession $0\mathrm{.}205\%$

What is the expected standard deviation for KMP stock?

A$)6\mathrm{.}91\%$

B$)8\mathrm{.}13\%$

C$)7\mathrm{.}79\%$

D$)7\mathrm{.}25\%$

E$)8\mathrm{.}85\%$

I need the explinatio of each equation $($ just wirte it beside every answer $)$