During the construction of the Beijing-Zhangjiakou Railway, Jeme Tien Yow________.
A、felt ashamed for the work relied on foreigners
B、used Rackarock for the first time in the excavation of caves
C、decided to dig two shafts above Badaling Tunnel and then excavated to both ends to form six excavation faces to accelerate the progress of the project
D、reduced the cost of the project greatly and completed the construction as scheduled