Answer:
The first plan of $49 will be best plan for her.
Step-by-step explanation:
Katherine used 1479 minutes call in the last 6 months.
So, the average monthly call that Katherine made is minutes.
Now, there are two plans for mobile recharge.
One is 250 minutes call time for $49 and the other is 350 minutes call time for $65.
Since 246.5 < 250 and Katherine does not want to spend more for minutes she won't use, then the first plan of $49 will be the best plan for her. (Answer)