That rule is applicable …… every one. A. to B. for C. about D. with

The correct answer is A. to.

The word “applicable” means “able to be applied”. In this sentence, the rule is being applied to everyone. Therefore, the correct preposition is “to”.

The other options are not correct because they do not make sense in the context of the sentence.

• “For” is used to indicate a purpose or reason. In this sentence, the rule is not being used for a purpose or reason.
• “About” is used to indicate a topic or subject. In this sentence, the rule is not about a topic or subject.
• “With” is used to indicate a relationship or association. In this sentence, the rule is not related to or associated with anyone.