Concept:Identify which given sentences are grammatically correct and contextually meaningful.Explanation:Sentence A is correct because it is grammatically accurate and clear in meaning.Sentence B is correct because it is grammatically accurate and contextually complete.Sentence C is incorrect because it has grammatical errors: "disciplined" should be "discipline", and the quoted phrase "party's president" needs proper punctuation.Thus, only A and B are correct.Answer:The correct set of sentences is A and B, which is Option E.