Answer:
Option C is the correct answer.
Explanation:
Probability is the ratio of number of favorable outcome to total number of outcomes.
Here we need to find probability that repair person is equally likely to be at your apartment any time during the appointment time.
A repair person is scheduled to be at your apartment between 9:00am to 12:00pm.
Total duration for which repair person available = 3 hours.
You have to leave at 11:30 to help out a friend,
Time you are available at home during this 9:00am to 12:00pm, is 9:00am to 11:30 am
Duration favorable = 11:30 - 9:00 = 2:30 hours = 2.5 hours
![\texttt{Probability = }(2.5)/(3)=0.8333=83.33\%](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5l52c3s3cbw6amukc4je9o36s7oxen7ho8.png)
Option C is the correct answer.