Two tuning forks have frequencies 380 and 384 hertz respectively. When they are sounded together, they produce 4 beats. After hearing the maximum sound, how long will it take to hear the minimum sound [MP PMT/PET 1998]
(a) $1 / 2 \mathrm{sec}$
(b) $1 / 4 \mathrm{sec}$
(c) $1 / 8 \mathrm{sec}$
(d) $1 / 16 \mathrm{sec}$