A signal $$m_{1}$$ (t) is band limited to 3.6 kHz and the three other signals $$m_{2}(t), m_{3}(t)$$ and $$m_{4}(t)$$ are band limited to 1.2 kHz each, and these signals are transmitted by means of TDM. Then, what will be the transmission bandwidth of the channel.

A

7.2 KHz

B

14.4 KHz

C

3.6 KHz

D

2.4 KHz