An e.m.f of 250 microvolt in induced in a coil when current in it changes from 10A to 6A in 0.4 second. What is the self inductance of the coil?

Question

(a) $25 \times 10^{-5} H$
(b) $2.5 \times 10^{-5} H$
(c) $25 \times 10^{-6} H$
(d) $2.5 \times 10^{-6} H$