Ana

Cheung

is getting ready to open a small restaurant. She is on a tight budget and must choose between the following long-distance phone plans:

Plan A:	Pay 9 cents per minute of long-distance calling.
Plan B:	Pay a fixed monthly fee of $14 for up to 320 long-distance minutes, and 5 cents per minute thereafter (if she uses fewer than 320 minutes in any month, she still pays $14 for the month).
Plan C:	Pay a fixed monthly fee of $22 for up to 460 long-distance minutes and 4 cents per minute thereafter (if she uses fewer than 460 minutes, she still pays $22 for the month).

Required Which plan should Cheung choose if she expects to make 100 minutes of long-distance calls? 320 minutes? 520

minutes?