Please help

How was Japan able to re-build its economy so quickly after the
destruction of World War II?

A) Japan found importing manufactured goods from other places
better than rebuilding their industrial complexes.

B) Japan's population was largely unskilled and uneducated,
which made finding factory workers easy.

C) Japan's government ended all tariffs and regulations that
impeded free trade.

D) Japan was able to focus all its resources in its economy due to
U.S. military protection.