we need the height
we draw some lines to get a special right triangle: a 30-60-90 triangle
we know that if the hypotonuse is 2x then the side oposite the 60 degree is x√3
so
6=hyptohuse=2x
3=x
3√3=height
so
area=length times height
area=8 times 3√3=24√3 cm²
answer is 3rd option