The answer to this question would be 5 bit
One bit can be used to code either 0 or 1. That means every one bit there is two possibility. Two bit can contain 4 possible way to code, three bit will be 8. That will go as [tex] 2^{x} [/tex] where x is number of bit. In this case, there is 26 letter with space so there is a total of 27 possible code needed. Then you will at least need 5 bit which gives you [tex] 2^{5} or 32 possible way
