Which letter-cluster will replace the question mark (?) in the following letter-cluster series?
MIWQX, MIWQY, MIWSX, MIZQX, ?, RIWQX
1
MNWQX
2
MMWRX
3
MMXQX
4
MMWQX
Which letter-cluster will replace the question mark (?) in the following letter-cluster series?
MIWQX, MIWQY, MIWSX, MIZQX, ?, RIWQX