Select the related word from the given alternatives: Flow is to River as Stagnant is to which type of water body?

Introduction / Context:
This verbal analogy question tests your understanding of how descriptive words relate to the nouns they commonly qualify. The pair Flow : River is given, and you must decide which word best completes the analogy Stagnant : ? from the options. Questions like this are very common in aptitude and government exams, and they check whether you can recognise natural, real world pairings in English usage.

Given Data / Assumptions:
1) Flow is a word that often describes the movement of a river or stream.
2) A river is a natural water body that normally moves continuously from a higher level to a lower level.
3) Stagnant describes water that is still, unmoving, and often collected in one place.
4) The answer options are Pond, Rain, Stream, and Canal.
5) We assume standard everyday English usage, not rare or technical meanings.

Concept / Approach:
The relationship between Flow and River is that of a typical verb or state that is strongly associated with a particular type of water body. When people talk about rivers, they frequently refer to the flow of the river. To complete the analogy, we need to find the water body that is most naturally described as stagnant. In everyday language, stagnant water is most commonly linked with ponds and small pools, where water stays still for long periods.

Step-by-Step Solution:
Step 1: Restate the first pair. Flow is a natural action or condition of a river, which normally moves and does not remain still. Step 2: Understand the word stagnant. Stagnant water is water that does not move, often collected in one place, and may become dirty or unhealthy over time. Step 3: Check each option as a water body. A pond is a small, usually still body of water. Rain is water that falls from the sky and is not a stored water body. A stream is a flowing body of water similar to a small river. A canal is an artificial waterway that usually has moving water. Step 4: Identify which option is most naturally linked with stagnant water. Ponds are often described as having stagnant water if there is no inflow or outflow. Step 5: Conclude that Pond is the best match for Stagnant, in the same way that River matches Flow.

Verification / Alternative check:
If we try to pair stagnant with rain, stream, or canal, the combinations sound unnatural. People do not normally say stagnant rain, stagnant stream, or stagnant canal, but stagnant pond is a very common expression. This confirms that Pond is the only option that fits as naturally as Flow fits with River.

Why Other Options Are Wrong:
Rain refers to falling water, which moves downward and does not sit still in one place. A stream is defined by flowing water, which is the opposite of stagnant. A canal also normally carries moving water for navigation or irrigation. None of these are primarily associated with still, unmoving water the way ponds are, so they fail to mirror the original relationship.

Common Pitfalls:
A typical mistake is to focus only on water related words and choose any option that looks watery without thinking about the quality of movement. Another error is to match Flow with Stream, because streams also flow, and then attempt a similar pairing for stagnant. However, the question has already fixed Flow with River, so your task is only to complete the second part consistently with that pattern.

Final Answer:
The correct completion of the analogy is Stagnant : Pond, so the answer is Pond.