Water course (source to sink): Arrange— a. Ocean, b. Rivulet, c. Sea, d. Glacier, e. River.

Introduction / Context:
Hydrological reasoning: mountain ice gives rise to tiny streams, which form rivers that drain to seas and finally the global oceans.

Given Data / Assumptions:

• Glacier melt → rivulets → rivers.
• Rivers often empty into seas, which are marginal parts of the oceans.

Concept / Approach:
Order by natural flow from source to ultimate sink.

Step-by-Step Solution:

Verification / Alternative check:
Consistent with drainage basins and global ocean connectivity.

Why Other Options Are Wrong:
They place ocean/sea before upstream sources.

Common Pitfalls:
Confusing sea vs ocean; reversing source and mouth.

Final Answer:
d, b, e, c, a