Correct Answer: A
Explanation:
Grouping. So here grouping of letters is done. First 2 letters- M and O are grouped and last 2 letters S and E are grouped. After grouping, +1 is added and the position of the letters is interchanged. Like in MO group, +1 is added so the result will be NP and then the letters are interchanged and so the result for 1st group will be PN. Same for the second group and the middle odd letter is as it is.