A signalling system in which each letter of the alphabet is represented by a different symbol is not used because

Too many pulses per letter are required

It would be too difficult for an operator to memorize

Noise would introduce too many errors

A signalling system in which each letter of the alphabet is represente

1.	A signalling system in which each letter of the alphabet is represented by a different symbol is not used because
A.	It would be too difficult for an operator to memorize
B.	It is redundant
C.	Noise would introduce too many errors
D.	Too many pulses per letter are required
Answer» D. Too many pulses per letter are required