They offer visitors a sneak-peek at the underground life of Vietnamese soldiers back ___________ (6) 1948.

Choose the letter A, B, C or D to complete the passage below

The Cu Chi Tunnels are part of a massive war museum in Ho Chi Minh. They offer visitors a sneak-peek at the underground life of Vietnamese soldiers back ___________ (6) 1948. The site has over 120km of underground tunnels, with trapdoors, living areas, kitchens, storage facilities, armoury, hospitals, and command centres. After the war against the French, Vietnamese soldiers expanded ___________ (7) tunnels and included effective air filtration systems, which helped them survive the Cu Chi carpet-bombings. It is now one of Ho Chi Minh’s ___________ (8) iconic attractions. You can enjoy plenty of activities during your visit. A popular option ___________ (9) following the narrow routes of the underground tunnel. Before entering the underground tunnels, visitors watch a short film of Cu Chi Tunnels so that they can understand how the tunnel system works. There are emergency exit points every 10 metres for safety. The Cu Chi Tunnels are an hour's drive from Ho Chi Minh City. There are tour operators ___________ (10) can arrange for a half-day tour for VND 825,000 upwards.

(6) .................

• A. to
• B. in
• C. of
• D. on