SOLUTION —
$a^{3}+\frac{1}{a^{3}}$
$=\left(a+\frac{1}{a}\right)^{3}-3 \times a \times \frac{1}{a}\left(a+\frac{1}{a}\right)$
$=\left(a+\frac{1}{a}\right)^{3}-3 \times\left(a+\frac{1}{a}\right)$
$=(\sqrt{3})^{3}-3 \times \sqrt{3}$
$=3 \sqrt{3}-3 \sqrt{3}= 0 ;$ Ans.
So, The correct option is (B)