As per given by the question,
There are given that the trigonometric function,
[tex]4\cos \frac{5\pi}{3}[/tex]Now,
The general form of the rectangula form is,
[tex]a+ib[/tex]Now,
Written the given trigonometric in the form of complex,
So
[tex]Z=4\lbrack\cos \frac{5\pi}{3}+i\sin \frac{5\pi}{3}\rbrack[/tex]Then,
[tex]\begin{gathered} z=4\lbrack\cos \frac{5\pi}{3}+i\sin \frac{5\pi}{3}\rbrack \\ z=4\lbrack\cos (300)+i\sin (300)\rbrack \end{gathered}[/tex]Then,
[tex]\begin{gathered} z=4\lbrack\cos (300)+\text{isin}(300)\rbrack \\ z=4\lbrack0.5+i(-0.866)\rbrack \\ z=2+i(-0.866\times4) \\ z=2-i3.46 \\ z=2-2\sqrt[]{3}i \end{gathered}[/tex]Hence, the option c is correct.