Split1) Parallelism: "joined, was injured, was discharged". By this rule B, C, D and E are out.
Split2) "while being" or "having been" both are red flags. B and E are out.
Split3) Logical Predication and meaning: the original sentence has past perfect "had become + too ill" and simple past " was discharged". This means that she was ill before she joined the army and was discharged after once she had come too ill to continue. The meaning is preserved.
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Split2) "while being" or "having been" both are red flags. B and E are out.
Split3) Logical Predication and meaning: the original sentence has past perfect "had become + too ill" and simple past " was discharged". This means that she was ill before she joined the army and was discharged after once she had come too ill to continue. The meaning is preserved.
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