In the sentence "He did not abide with my decision.", the underlined preposition must be checked. Choose the option that best improves the phrase, or select no improvement if the sentence is already correct.

Introduction / Context:
This sentence improvement question tests knowledge of fixed verb plus preposition combinations. The verb abide has a particular preposition that follows it when we want to say someone obeys or accepts a rule, law, or decision. The sentence describes a person who did not follow a decision, so you must choose the preposition that correctly expresses this idea in standard English.

Given Data / Assumptions:

• Sentence: He did not abide with my decision.
• The underlined part is abide with my decision.
• Options: to, by, for, no improvement.
• The intended meaning is that he did not accept or obey the decision.

Concept / Approach:
The correct phrase in English is abide by, as in abide by the rules or abide by the decision. Abide with is not standard when we mean obey or follow. Abide by conveys the sense of accepting and acting according to a rule, law, or agreement. Therefore, the correct preposition in this context is by. The other options either form incorrect combinations or do not express the intended meaning.

Step-by-Step Solution:
Step 1: Identify the main verb and its object: abide and my decision. Step 2: Recall the fixed combination abide by, which means obey or accept, as in abide by the decision of the court. Step 3: Replace with with by to form the correct phrase abide by my decision. Step 4: Check option B, by, which yields the sentence He did not abide by my decision. This correctly expresses that he did not follow the decision. Step 5: Evaluate option A, to. Abide to my decision is not idiomatic and does not appear in standard English. Step 6: Evaluate option C, for. Abide for my decision also does not form a recognised phrasal structure and fails to convey obedience. Step 7: Reject no improvement because abide with my decision is not the standard collocation in this meaning.

Verification / Alternative check:
Consider other sentences where abide is used correctly: Citizens must abide by the law, We should abide by the terms of the contract, Players are expected to abide by the rules of the game. In all these examples, the preposition by follows abide. Replacing by with with, to, or for would sound unnatural or incorrect. Applying the same pattern to the exam sentence confirms that abide by my decision is the correct form.

Why Other Options Are Wrong:
To and for do not form standard combinations with abide when the meaning is obey or accept. They would confuse the reader and be marked wrong in formal writing. No improvement preserves the incorrect phrase abide with my decision.

Common Pitfalls:
Many phrasal verbs and prepositional verbs in English must be learned as complete units, because changing the preposition changes or destroys the meaning. It can be tempting to treat with as a general purpose preposition, but verbs such as abide, agree, comply, and concur pair with specific prepositions like by, to, with, or in. Learning these pairs through reading and practice will greatly improve your performance in usage and error spotting questions.

Final Answer:
The correct improvement is by, giving: He did not abide by my decision.