Choose the correct option for the following question.

Concept: In a figure series alternating between a "separate" frame (three shapes drawn independently, side by side) and a "nested" frame (one shape enclosing the other two), a fixed positional rule links each nested frame to the separate frame immediately before it: reading that separate frame left to right, the rightmost shape becomes the nested frame's outer container, the middle shape is placed inside as the upper shape, and the leftmost shape is placed inside as the lower shape.

Application to this series:

1. Frame 1 (separate) reads square, circle, triangle from left to right.

2. Applying the rule to Frame 1: the rightmost shape, the triangle, becomes Frame 2's outer container; the middle shape, the circle, sits upper inside it; the leftmost shape, the square, sits lower inside it — exactly matching the given Frame 2 and confirming the rule.

3. Frame 3 (separate) reads triangle, square, circle from left to right.

4. Applying the same rule to Frame 3: the rightmost shape, the circle, becomes Frame 4's outer container; the middle shape, the square, sits upper inside it; the leftmost shape, the triangle, sits lower inside it.

Cross-check: Modelling the series as one continuous rotation through three fixed structural slots — leftmost/lower-inner, middle/upper-inner, and rightmost/outer — held constant across both separate and nested styling: from Frame 1 to Frame 2 the assignment does not change (only the drawing style switches from separate to nested), so the square stays in the lower-inner slot, the circle in the upper-inner slot, and the triangle in the outer slot. From Frame 2 to Frame 3 every shape advances by exactly one slot (square to the middle slot, circle to the rightmost slot, triangle wrapping to the leftmost slot), giving triangle, square, circle — matching the given Frame 3. Holding the same style-preserving assignment for the Frame 3-to-Frame 4 step, since it is again a separate-to-nested transition like Frame 1 to Frame 2, reproduces the identical result.

Answer: The figure with the circle as the outer container, enclosing the square positioned upper and the triangle positioned lower, completes the series.