The correct option is C Earcel
Following is the list of ARPU:
AirLetAllianceDofaphoneEarcelBainsNLARPU Jan 104.710.497.510.79ARPU Jan 114.29.48.6713.049.6
It can be seen clearly that Earcel is maximum for both the years. Hence it will be maximum combined also. Hence, option (c) is the answer.
Alternatively, it can be observed that all the bars except Earcel give less than 10 ARPU in the 1st year and in 2nd year, Earcel is maximum.