Odd Man Out

In all other pairs, One number is the square of the other.

In all other groups, the third and first letters are alternate letters, while the first two letters are consecutive letters of the alphabet.

All except Cycle run on fuel.

Each of the numbers except 83, is divided by 3.

All except Roof are dwelling places of different animals.

All except Home represent a collection of dwelling units with the required infrastructure.

25 – 21 = 4 = 2² 61 – 12 = 49 = 7² 34 – 30 = 4 = 2² 44 – 31 = 13 (which is not a square of any number)So, option (C) is the answer.

In all other groups, the third letter is four steps ahead of the second letter which, in turn, is two steps ahead of the first letter.

Except Vision, all others are the internal part of an eye.

All except Bevin were the Prime Ministers of UK, while Bevin was the Foreign Secretary of UK.