$(7.)$ A $2$ kg rock is thrown at a $32$ upwards angle from the top of a cliff, with an initial speed of $20\frac{m}{s}.$ The cliff is $h=28m$ high. What is the rock's speed when it reaches a height of $\frac{h}{2}?$

A$)36\frac{m}{s}$

B$)26\frac{m}{s}$

$($C$)11\frac{m}{s}$

D$)31\frac{m}{s}$

E$)16\frac{m}{s}$

I know the correct answe is B $(26$m$/$s$)$ but im not sure how to get it