A uniformly would soleacidal (ie) of self inductance $8 \times 10^{-4}\;H$ and resistance $45\;L$ is broken into two identical coils. These colis are then connected in parallel across a battery of $10V$ of negligible resistance the time constant for this circuit is

Question

$(a)\;4 \times 10^{-4}\;S \\ (b)\;\frac{1}{2} \times 10^{-4}\;S \\(c)\;2 \times 10^{-4}\;S \\(d)\;1 \times 10^{-4}\;S$