【单选题】

Why does the author mention that Japan "ranks only 30th in the world as a tourist destination— about the same as Tunisia and Croatia" in Paragraph 8
A．(A) To prove that Tunisia and Croatia maintain a healthy competitive edge.

B．(B) To criticize Japan for not courting foreign travelers.
C．(C) To prove that the standard of living in Japan lags behind world standards.
D．(D) To prove that tourism plays an important role in maintaining a country's competitive edge.