The managers of a large urban metro system are concerned that the system's current operations are leading to an inefficient consumption of energy and are looking for ways to improve its sustainability. What is a solution that could be adopted to make the metro system more sustainable?
A.Install a mainframe computer on each train to gather data on its energy consumption.
B.Install a year-round cooling systern to reduce fluctuations in temperature controls.
C.Use machine learning to optimize the frequency of train routes based on passenger load.
D.Provide passengers with electronic devices that track when they board and exit the trains
