单选题 Rail transport is an important mode of long-distance transportation in China. Almost all rail operations are handled by the China Railway Corporation. According to the railway network development plan, by 2020, China's total mileage of railway will achieve 150 thousand kilometers, of which high-speed railway will achieve 30 thousand kilometers. By the end of 2017, China has built 127 thousand km of railways, including 25 thousand kilometres of high-speed rail. A grid network with four horizontal and four vertical tracks has been formed, including the Beijing-Shanghai high-speed rail line, and the Beijing-Shenzhen-HongKong high-speed rail line. China has the second longest railway network and the longest high speed railway network in the world. China's railways are the busiest one in the world. Freight traffic turnover has increased more than fivefold over the period 1980-2013 and passenger traffic turnover has increased more than sevenfold over the same period. In 2014, railways in China delivered 2.357 billion passenger trips, generating 1,160.48 billion passenger-kilometers and carried 3.813 billion tons of freight, generating 2,753 billion cargo ton-kilometers. In 2017, China Railways delivered 3.039 billion passenger trips, got an increase of 9.6% over the same period of 2016. 1.171 billion passengers of which were sent by high speed trains, accounting for 56.4% of the total. There were 2.2918 billion tons of goods were sent in 2017 by railway, got an increase of 10.1% over the same period of last year. Driven by need to increase freight capacity, the railway network has been expanding rapidly. China built 9,000 km of new railway in 2015, and 3038 km in 2017. China has a long term plan to expand the network to 274,000 km by 2050小题:How many passenger trips were delivered by China Railways in 2017