(d) For current to be maximum , $X_{L} = X_{C}$
Hence, resonant frequency
$f = \frac{1}{2\pi} = \frac{1}{\sqrt{LC}} = \frac{1}{\sqrt{0.5 \times 8 \times 10^{- 6}}} = \frac{10^{3}}{4\pi}$
But angular frequency
$\ \ \ \ \ \ \ \ \ \ \ \omega = 2\pi f$
$\omega = \frac{2\pi \times 1000}{4\pi} = 500\ Hz$