Correct option is B
Given,
· Amongst six friends B,I,H,J,O and U, each has a different height.
· H is taller than only four other friends.
· O is taller than only one friend.
· B is taller than U but shorter than J.
· J is not the tallest.
From the given information, we get:
I > H > J > B > O > U
So, U is the shortest among all the friends.
Thus, correct option is (b).