A.
Deposits of natural gas in Japan have been exhausted.
B.
The largest deposits of natural gas available to Japan are located in the islands in the South China Sea and Japan and China have a dispute about who owns those islands.
C.
A tsunami in 2011 damaged the nuclear reactor in Fukushima causing Japan to shut down all of its nuclear generation of electricity.
D.
Japan imposed strict environmental requirements for the generation of electricity that can only be met by using natural gas to produce electricity.