The highest tunnel for high-speed train in the world has been recently opened in:
সমাধান
সঠিক উত্তর: Option C
The world’s highest tunnel for high-speed train in northwest China at an altitude of 3607.4 metres became operational on 1 May 2014. The 16.3 km long tunnel links Gansu province and Xinjiang provinces. The tunnel passes through the Qilian Mountains with two sections and bridge.
