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This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Nanjing is the transportation hub in eastern China and the downstream Yangtze River area. Different means of transportation constitute a three-dimensional transport system that includes land, water and air. As in most other Chinese cities, public transportation is the dominant mode of travel of the majority of the citizens. As of October 2014, Nanjing had five bridges and two tunnels over the Yangtze River, which are tying districts north of the river with the city centre on the south bank.
Output:
What are the three types of transport in Nanjing?