Answer:
Without the full context of the paragraph, it is difficult to determine the exact purpose. However, based on the provided options, the purpose of the paragraph starting with the word "Another" appears to be to explain the problem that donor organs don't work well for everyone. The paragraph likely discusses how even though donor organs can save lives, they are not always a perfect match for the recipient's body and may cause complications or rejection. The purpose of the paragraph may be to highlight the challenges and limitations of organ transplantation and the need for continued research and improvement in the field.