Q. To avoid the wastage of memory, the instruction length should be

Explanation by: Sikhar Chaudhary

Character size is one of the influence on a choice of word size. Before the mid 1960s, characters were most often stored in 6 bits; this allowed no more than 64 characters 80 alphabets were limited to upper case. Since it is efficient in time and space to have the word size be multiple of the character size, word sizes in this period were usually of 6 bits (in binary machines). A common choice then was the 36-bit word.