HEY THERE!!
AS WE KNOW cotx = base / perpendicular
and cscx = hypotenuse / perpendicular.
Here base = 4 and perpendicular = 3
So we have to find hypotenuse
Using trigonometry trick.
[tex]{H}^{2} = {B}^{2}+ {P}^{2}[/tex]
{H}^{2} = 16+ 9
taking squre root on both sides.
H = 5
now cscx = 5/3
SO YOUR ANSWER IS (D)5/3
HOPE IT HELPED YOU.