A cellular phone company charges a monthly base fee plus an additional cost per gigabyte of data used. The graph shows the total monthly cost, in dollars, for gigabytes of data used. The line passes through and . What is the best interpretation of the -intercept of the graph?
The cost of each gigabyte of data is $20.
The total monthly cost is $45 for 5 gigabytes of data.
The monthly base fee is $20.
The total monthly cost increases by $25 for every 5 gigabytes of data used.
