Answer: b) Per incident plan is cheaper.
Step-by-step explanation: We are given according to first case:
Rate per month = $100.
Second case :
Rate per incident = $200.
According to rate per month plan, the total amount after 3 months would be
= 3×$100 = $300.
And according to per incident plan total amount after 3 months would be $200 because it is said that there expect to average one incident per three months.
So, total amount according to second plan is just $200.
So, we can see than $200 is obviously less than $300.
Therefore,
b) Per incident plan is cheaper.