Answer: first option 0 to 30 minutes.
Jusitification:
Interpolation is the prediction of an intermediate value using a linear model.
In this case, she has the data for 0, 5, 10, 15, and 30 minutes.
So, she can interpolate between any pair of consecutive data to find an intermediate value.
For example: i) if she wants the value for 20 minutes, she can interpolate between 15 and 30 minutes, ii) if she wants the value for 7 minutes, she can interpolate between 5 and 10 minutes, iii) if she wants the value for 12 mintues, she will interpolate between 10 and 15 minutes.