[tex]\mathfrak{\huge{\orange{\underline{\underline{AnSwEr:-}}}}}[/tex]
Actually Welcome to the concept of trigonometry.
Here, we use the Sine ratio.
Sine 60° = 21/x
===> since sin60° = √3/2
==> x = 21*2/√3
==> x = 42/√3
rationalizing we get as,
==> 42√3/3 ===> 14√3
hence, x = 14√3 units,
so finally, x = 14√3 , option C.) is correct.
