Arrange the following water bodies from smallest to largest: (a) Ocean (b) Sea (c) Pond (d) River.

Introduction / Context:
This tests comparative size ordering of common water bodies.

Given Data / Assumptions:

• Pond — smallest, localized water body.
• River — flowing body, larger than a pond.
• Sea — part of the ocean, larger than rivers.
• Ocean — largest continuous body of salt water.

Concept / Approach:
Order by typical scale: Pond < River < Sea < Ocean.

Step-by-Step Solution:
Sequence: c → d → b → a.

Why Other Options Are Wrong:
They misplace sea/ocean or place pond after river/sea.

Final Answer:
c, d, b, a