Computer Access to International Data Network a Costs $10 Per

Multiple Choice

Computer access to international data network A costs $10 per day plus $8 per hour or fraction of an hour. Network B charges $15 per day, but only $6 per hour or fraction of an hour. In the illustration, t represents the connect time and C represents the total cost for each network. Find the minimal daily usage (in hours) after which it would be more economical to use network B.

A) After 2.5 hours, network B is cheaper.
B) After 1.5 hours, network B is cheaper.
C) After 2 hours, network B is cheaper.
D) After 1 hour, network B is cheaper.
E) After 3 hours, network B is cheaper.