The logic follows here is:
1) Y is taller than only U
This means U will be the last person or the smallest person of all the other person.
Therefore, we can arrange them as
_ > _ > _ > _ > Y > U.
2) Z is taller than only two persons
We know, Y and U are the smallest persons of all.
This means Z is taller than Y and U.
Therefore, we can arrange them as
_ > _ > _ > Z > Y > U.
3) Two persons are either taller or smaller than V.
From the above statements, it is clear that no two person are smaller than V.
Therefore, there is only one possibility of having two persons taller than V.
The order can be formed like this,
_ > _ > V > Z > Y > U.
4) W is taller than Z but not the tallest.
We can arrange W ahead of V which can satisfy the given condition.
_ > W > V > Z > Y > U.
Now, the final arrangement will be
X > W > V > Z > Y > U.
Therefore, X will be the tallest person.
Hence, the correct answer is X.
Confusion PointsDon't confuse in W is taller than Z.
It is not given that W is taller than only Z.
Hence, we can put W ahead of Z anywhere according to the condition given.