Explanation:

Let’s break down the statements:

- Five persons are in a row, facing north.

- Leftmost and rightmost ends: One is an introvert, the other is an extrovert.

- Thin person is immediately right of the intelligent person.

- Weak person is immediately left of the extrovert.

- Intelligent person is exactly between introvert and thin persons.

Stepwise:

1. Arrange introvert (I) and extrovert (E) at ends.

2. I _ _ _ E OR E _ _ _ I

3. Intelligent (Int) is between I and Thin.

- So: I Int Thin _ E or E _ Thin Int I

- But Thin is immediately right of Intelligent person. So, I Int Thin _ E

4. Weak person is immediately left of extrovert.

- So before E, the weak person (W) sits.

- I Int Thin W E

Now, check who is sitting in the middle (3rd position):

- I (1), Int (2), Thin (3), W (4), E (5)

The Thin person is at the centre.

Correct Answer: Option 4 – Thin.