In this sentence-improvement question on superlative noun phrases, decide which phrase, if any, should replace the highlighted words "the vilest of the thing that can be done by a person" in the sentence "The vilest of the thing that can be done by a person is to ill-treat dogs and other defenseless animals."

Introduction / Context:
This question checks your understanding of the correct structure with superlative adjectives and singular nouns. The sentence is: "The vilest of the thing that can be done by a person is to ill-treat dogs and other defenseless animals." The highlighted part is "the vilest of the thing that can be done by a person". You must decide which suggested alternative, if any, gives a grammatically correct and natural expression of the idea that ill-treating defenseless animals is the worst possible thing a person can do.

Given Data / Assumptions:

• Original phrase: "the vilest of the thing that can be done by a person".
• Option (i): vile things that can be done by persons.
• Option (ii): vilest things that can be done by a person.
• Option (iii): vilest thing that can be done by a person.
• The sentence is meant to highlight a single worst action: ill-treating dogs and defenseless animals.

Concept / Approach:
The word "vilest" is the superlative form of "vile", so it refers to something that is the worst among all. When we speak of one worst action, we should use a singular noun "thing" without "of the" between the superlative and noun. The correct structure is "the vilest thing that can be done by a person". The original phrase "the vilest of the thing" is ungrammatical, and options that use plural "things" are not suitable because the sentence clearly points to one particular act as the single vilest action.

Step-by-Step Solution:
Step 1: Notice that the sentence is comparing different actions a person can do and calling one of them the worst (vilest). Step 2: Understand that the intention is to say: "The vilest thing that can be done by a person is to ill-treat dogs and other defenseless animals." Step 3: Check the original phrase: "the vilest of the thing that can be done" – the combination "of the thing" after a superlative is not acceptable with a singular noun. Step 4: Evaluate option (i) "vile things that can be done by persons" – this is plural and general; it lists all vile things, not the single vilest thing. Step 5: Evaluate option (ii) "vilest things that can be done by a person" – again this plural "things" conflicts with the idea of one single vilest action. Step 6: Evaluate option (iii) "vilest thing that can be done by a person" – this singular form correctly presents just one worst action. Step 7: Conclude that option (iii) is the correct replacement.

Verification / Alternative check:
Insert option (iii) into the sentence: "The vilest thing that can be done by a person is to ill-treat dogs and other defenseless animals." This flows naturally and clearly states that among all possible actions, ill-treatment of defenseless animals is the most vile. It matches the intended structure: definite article ("The"), superlative adjective ("vilest"), singular noun ("thing"), and relative clause ("that can be done by a person"). No other option achieves this combination accurately.

Why Other Options Are Wrong:
Option (i) "vile things that can be done by persons" talks about several vile things, not the single vilest one, so it changes the meaning. Option (ii) "vilest things that can be done by a person" is grammatically possible but logically odd: it suggests several "vilest" things, which contradicts the usual idea of a single worst action. The original phrase "the vilest of the thing" is clearly ungrammatical in standard English usage.

Common Pitfalls:
Candidates sometimes overlook the singular versus plural contrast when choosing between very similar options. When a sentence highlights "the worst thing", "the best way", "the finest example", you should expect a singular noun after the superlative. Another common mistake is to accept "of the thing" because they have seen similar patterns like "the best of the students", which is used with plural nouns. Always check whether the noun following the superlative is singular or plural and choose the correct pattern accordingly.

Final Answer:
The correct replacement is Only iii, giving the phrase "the vilest thing that can be done by a person".