Arrange basic geometric notions from simplest to more complex shapes. Items: (a) Line (b) Angle (c) Square (d) Triangle

Introduction / Context:
From elementary geometry: line → angle (two rays) → triangle (3 angles) → square (4 equal sides/angles).

Given Data / Assumptions:
We build complexity stepwise.

Concept / Approach:
Conceptual dependency: an angle needs lines; polygons need angles; quadrilaterals follow triangles in complexity.

Step-by-Step Solution:

Verification / Alternative check:
Count of sides/angles increases monotonically.

Why Other Options Are Wrong:
They start with a shape or mix order.

Common Pitfalls:
Confusing “line” vs “angle” prerequisites.

Final Answer:
a, b, d, c