In this set of letter groups, (4) XZ is different from the others because the other letter groups represent consecutive letters in the English alphabet, while XZ does not.
● BC represents the letters B and C.
● MN represents the letters M and N.
● PQ represents the letters P and Q.
● ST represents the letters S and T.
However, XZ represents two non-consecutive letters in the alphabet.
The Correct option is(D)