Correct option is D
Given:
M, N, O, P, Y and Z live on six different floors of the same building.
The lowermost floor in the building is numbered 1, the floor above it, number 2 and so on till the topmost floor is numbered 6.
Only three people live between Y and Z, where Y lives below Z.
Z does not lives on top most floor.
P lives on an odd numbered floor.
O lives on one of the floors below M and on one of the floors above N.
From the above following arrangement will be -

From the above arrangement O lives on floor numbered 4.
Correct answer is (d) O.