Final answer:
The sentence 'She hasn't come yet. Hasn't she come yet?' logically pairs a statement with its interrogative form, using proper grammar and expressing an expectation.
Step-by-step explanation:
The sentence that makes the most sense is B. She hasn't come yet. Hasn't she come yet? This pair of sentences uses negative and interrogative forms correctly to express an expectation that 'she' might have already arrived. Sentence A has an inconsistency in meaning as the two parts contradict each other; while sentence C could be grammatically correct depending on context, it is less common to repeat the 'yet' in the question form.