Once you attempt the question then PrepInsta explanation will be displayed.

Let the six students be R, D, K, S, J and H

Kholi has more people behind him than in front of him

So he occupies position 1, 2 or 3 from front

Case 1 ⇒ K _ _ _ _ _

Case 2 ⇒ _ K _ _ _ _

Case 3 ⇒ _ _ K _ _ _

Also there are exactly two people Kholi and Jadeja.

Case 1 ⇒ K _ _ J _ _

Case 2 ⇒ _ K _ _ J _

Case 3 ⇒ _ _ K _ _ J

Samson is the shortest among the six

So Case 1 is not possible

Case 2 ⇒ S K _ _ J _

Case 3 ⇒ S _ K _ _ J

Rohit and Dhavan stand next to each other

Case 2 ⇒ S K R D J H (or) S K D R J H

Case 3 ⇒ S H K R D J (or) S H K D R J

Hardik is shorter than Dhavan.

So case 2 is not possible

S H K R D J (or) S H K D R J

So tallest is Jadeja

So answer is (b)