A high$-$net$-$worth client invests one$-$half of her wealth in Stock $1$ and the remainder in Stock $2.$ The correlation coefficient between the two stocks is $1\mathrm{.}0.$ The total risk of the portfolio is closest to:

Expected Return Risk

Stock $18\%18\%$

Stock $212\%24\%$

Group of answer choices

$10\%.$

$18\%.$

$24\%.$

$21\%.$

$.$