Select the one word which best substitutes the phrase:\n"Decay of organic matter producing a fetid smell".

Introduction / Context:
This one-word substitution question comes from the vocabulary of decomposition and environmental science. The phrase describes the process by which organic matter decays and produces a foul, offensive odour. The technical term for this process is "putrefy" or "putrefaction", and the question asks for the verb that means "to undergo that kind of rotting".

Given Data / Assumptions:

• Phrase: "Decay of organic matter producing a fetid smell".
• Options: "Putrefy", "Crisp", "Neoteric", "Virgin".
• We assume the required answer is the verb describing this process.

Concept / Approach:
The primary concept is identifying which word carries the exact meaning of rotting with offensive smell. "Putrefy" is a specific verb that describes decomposition of organic matter, especially with production of a bad smell. The other options describe unrelated qualities such as freshness, newness, or innocence, so they can be eliminated. Recognising the root "putrid" meaning foul-smelling can help you connect it to "putrefy".

Step-by-Step Solution:
Step 1: Understand the phrase. It describes rotting organic material that gives off a bad, fetid odour.Step 2: Examine "Putrefy". This verb means to rot or decay, especially with a strong, unpleasant smell, precisely matching the description.Step 3: Examine "Crisp". This is an adjective meaning firm, fresh, or brittle, often used for food or weather. It is almost the opposite of decayed.Step 4: Examine "Neoteric". This adjective means modern or recent, related to newness, not decomposition.Step 5: Examine "Virgin". This adjective refers to something pure, untouched, or unused; again this is associated with lack of contact or corruption, not decay.Step 6: Conclude that "Putrefy" is the only option that expresses the rotting process described in the phrase.

Verification / Alternative check:
Test "putrefy" in example sentences: "The meat began to putrefy in the heat", meaning it started to rot and smell bad. This fits the phrase "decay of organic matter producing a fetid smell". None of the other options can be substituted: "the meat began to crisp" or "the meat became neoteric" or "the meat became virgin" are either meaningless or directly contrary to the idea of decay.

Why Other Options Are Wrong:

• "Crisp": Associated with freshness, firmness, or pleasant texture, not decay.
• "Neoteric": Relates to newness or modernity and has no connection to decomposition.
• "Virgin": Suggests purity or unused status and is conceptually the opposite of something decayed.

Common Pitfalls:
Some candidates might be misled by unfamiliar words like "neoteric" and assume that the rarest or most obscure term must be correct. However, the key is not obscurity but precise meaning. Recognising roots is helpful: "putre-" in "putrefy" is related to "putrid", meaning rotten. Developing root-based vocabulary helps greatly in these one-word substitution questions.

Final Answer:
The correct one-word substitute for "Decay of organic matter producing a fetid smell" is "Putrefy".