I would think the answer is B. Since it says "all the <em>soul</em> and <em>body</em> scars" I related it to answer B with it saying "is the physical and emotional pain". And the last line can refer to the last part of answer B.
B. Is the physical and emotional pain humans suffer worth it?
Explanation:
Robert Frost highlights the "soul-and-body scars", which can be translated as physical and emotional hardships faced by humans. Frost then asks the "men of earth" if it is worth it to endure all of those hardships in order to be alive ("to pay for birth").
Therefore, the answer is alternative B. Is the physical and emotional pain humans suffer worth it?
