Explanation:

Let's break down the statements:

- I is at the extreme left.

- So the lineup starts with I.

- II is second from the extreme right.

- So only one person is to the right of II.

- V and II are together.

- They must stand next to each other.

- V and III are together.

- So III also stands with V (so III, V, II form a group).

- Arranging these clues:

1. I is at the extreme left.

2. V is together with II and with III. This means III, V, II are together, in some order.

3. II is second from the extreme right; so the positions are: __ __ __ II __.

4. That means only one person is at the rightmost (extreme right).

- Let's fill in: I __ __ II __

- V and II must be together, as well as V and III together, so only possible arrangement:

- I III V II IV

- Here, IV is at the extreme right.

Now, let's look at options:

- Option 1: II

- Option 2: V

- Option 3: IV (Correct)

- Option 4: III

So, the person at the extreme right is IV.

Explanation:

- I is at the extreme left.

- II is second from extreme right.

- V is adjacent both to II and III, so they are together.

- Only IV remains for extreme right.

- So the correct answer is option 3: IV.