This question tests the fixed preposition that follows the verb "abide" when it means to obey or comply with rules.
- Option A (By): "Abide by" is the correct and only standard collocation meaning to accept and act according to a rule, decision, or law. This fits the sentence.
- Option B (On): "Abide on" is not a recognized English usage.
- Option C (To): "Abide to" is a common learner error and is not the correct preposition for this verb.
- Option D (In): "Abide in" exists but carries the different meaning of to live in or to remain in a place, not to obey rules.
The correct answer is A) By, so option 1 is the answer.