Solve. -ABC Phone Company Charges $21 Per Month Plus 8¢ Per

Solve.
-ABC phone company charges $21 per month plus 8¢ per minute of phone calls. XYZ phone company charges $15 per month plus 10¢ per minute of phone calls. How many minutes of phone calls in a month make XYZ phone company the better deal?

A) More than 30 minutes
B) Less than 300 minutes
C) Less than 30 minutes
D) More than 300 minutes