Juan is in the middle
<u>Explanation:</u>
Given:
Five students in total
_ _ _ _ _
Juan is not the shortest. So, Juan can be in 2nd, 3rd, 4th or 5th position.
_ J J J J
Tad is the tallest and not standing next to Juan, So,
_ J J _ T
Caroline is next to Tad. So,
_ J J C T
Juan is not standing next to Pamela. So,
P _ J C T
Marco is taller than Pamela. So,
P M J C T
The height is arranged in increasing order from Pamela to Tad.
Thus, from the series we can see that Juan is in the middle.