In order to increase the reliability of binary communication channel, the transmitted digits are 000 for 0 and 111 for 1. At receiving end, the decision is made by majority rule, that is, if at least two of three digits are 0, decision is taken in favour of 0 and so on. If p is error probability of one digit and pe is probability of making wrong decision in this scheme, then pe is:
1
p2
2
2p2
3
3p2
4
(1/3)p2