a b c d

d

$ P = VI$ $ I = \frac{P}{V} = \frac{1}{6}$ $R = \frac{V}{I} = 360\Omega$ $ \text{Impedance required is } Z = \frac{100}{1/6} = 600 \Omega$ $ X_L = \sqrt {z^2 - R^2} = 480\Omega$ $ L = \frac{X_L}{\omega} = \frac{480}{120\pi}= 1.28 H$