Syllogism — Propagate class inclusions for geometric terms Statements: I) All squares are rectangles. II) All rectangles are polygons. Decide the best conclusion about a square based on these statements.

Introduction / Context:
The prompt gives two universal inclusions about familiar geometric classes and asks you to pick the most accurate single conclusion about a square. This is a classic test of chaining inclusions without inventing extra claims or reversing directions.

Given Data / Assumptions:

• I: Squares ⊆ Rectangles.
• II: Rectangles ⊆ Polygons.
• Usual geometric meanings of 'square', 'rectangle', and 'polygon'; no other facts are assumed.

Concept / Approach:
Subset chains are transitive. If Squares ⊆ Rectangles and Rectangles ⊆ Polygons, then Squares ⊆ Polygons. Importantly, this does not erase the intermediate inclusion; it preserves both relationships simultaneously: every square is (i) a rectangle and (ii) a polygon.

Step-by-Step Solution:

Verification / Alternative check:
With a Venn diagram, place Squares inside Rectangles and Rectangles inside Polygons; Squares is thus inside Polygons as well. No contradiction arises, and both inclusions hold together.

Why Other Options Are Wrong:

• Square is not a polygon. Contradicts the derived inclusion Squares ⊆ Polygons.
• Square is a polygon only. Misleading/incomplete; it omits the guaranteed fact that every square is also a rectangle.
• Square is not a rectangle. Directly contradicts Statement I.

Common Pitfalls:
Picking a true-but-incomplete statement when a strictly stronger, fully accurate statement is available; forgetting that subset chains preserve all links.

Final Answer:
Square is a rectangle and a polygon.