The core elements of the pattern are circle, triangle, and square.
Let us consider the first option.
In this pattern, first three elements are circle, triangle, and square. These elements are continuing for the next round also.
So, the missing element is circle.
Let us consider the second option.
In this pattern, first three elements are triangle, square, and circle. These elements are continuing for the next round also.
So, the missing element is square.
Let us consider the third option.
In this pattern first three elements are square, circle, and triangle. These elements are continuing for the next round also.
So, the missing element is triangle.