With which of the following statements regarding the progress in China's metro construction would the author be most likely to agree?
A. The underway expansion, the improved urban commuting and travel, and the incredible engineering of tunneling through solid rock are the impressive features of China's metro service today.
B. A positive alternative to city congestion, a steady volume of passengers even at peak times, and the above-ground monorail system are the impressive features of China's metro service today.
C. The increased number of metro lines, the benefit from digital technologies,and the improved accessibility to stations are the impressive features of China's metro service today.
D. The competitive pricing, sufficient number of lines, conventional metros along with electric light rail lines are the impressive features of China's metro service today.