China
South Korea
Japan
Malaysia
Answer is Wrong!
Answer is Right!
The correct answer is (c) Japan.
The Seikan Tunnel is a railway tunnel under the Tsugaru Strait that connects the Japanese islands of Honshu and Hokkaido. It is the longest undersea tunnel in the world, and the longest tunnel of any kind in Japan. The tunnel was completed in 1988 and is 53.85 km (33.46 mi) long. It is used by the Shinkansen high-speed rail service.
The other options are incorrect. China does not have a railway tunnel that is longer than the Seikan Tunnel. South Korea has the Dosan Tunnel, which is 44.5 km (27.7 mi) long. Malaysia has the East Coast Rail Link, which is 688 km (427 mi) long, but it is not a railway tunnel.