It wold be D, like Nochillalisa said. There's more than 1 man. If it was man, then there would be no answer. But it's men, so it D.
Answer: Being generous is so important because it will come back to you later on in life. If you're mean to someone that might come back to you negatively.
It would be easier to answer if I could the poem
The answer is D because it is factual and unbiased since it's in a medical journal on the topic of the Spanish flu
