It would be 5 because its closer to five then it is 4
2/4=1/2 and 4/8
1/3=2/6 and 3/9
1/4=2/8 and 3/12
We have the following expression

This is equivalent to

Since

we have that

Therefore, the answer is the second option from top to bottom.
The average wait time is simply the averages of all the wait times in a product category. For instance, a custom watch manufacturer might have a wait time that ranges from 5 days to 10 days for a model A watch depending on the options. The average wait time for the model A watch is 7.5 days.