The correct answer is: A. St. Gothard road tunnel.
The St. Gotthard Road Tunnel is a highway tunnel in the Alps, crossing the Saint Gotthard massif between Göschenen in the canton of Uri in Switzerland and Airolo in the canton of Ticino. It is the longest road tunnel in the world, at 16.9 kilometers (10.5 mi). The tunnel was opened in 1980 and is part of the A2 motorway, which connects Basel in Switzerland to Chiasso in Italy.
The Mont Blanc tunnel is a highway tunnel under Mont Blanc, the highest mountain in the Alps. It connects Chamonix in France to Courmayeur in Italy. The tunnel is 11.6 kilometers (7.2 mi) long and was opened in 1965.
The Mersey (Queensway) tunnel is a road tunnel under the River Mersey in England. It connects Liverpool to Wallasey. The tunnel is 2.1 kilometers (1.3 mi) long and was opened in 1934.
The Orange Fish rivers tunnel is a road tunnel under the Orange Fish River in South Africa. It connects the towns of Aliwal North and Steynsburg. The tunnel is 1.8 kilometers (1.1 mi) long and was opened in 2003.