What should come in place of '?' in the given series based on the English alphabetical order?
MOR KMP IKN GIL ?
Refer to the given letter-cluster series and answer the question that follows.
AKMG, RTDC, WQCT, PILE, VTXF, HRXW
If in each of the letter-clusters, each letter is changed to the next letter in the English alphabetical order, how many letter-clusters thus formed will have exactly two vowels?