Which of the Following Actions Is Not an Example of the Application

Multiple Choice

Which of the following actions is not an example of the application of the method of residues?

A) Moving guests at a hotel where large numbers of guests became ill out of a suspected wing to see if the wing's climate control system is at fault.
B) Weighing an inflated balloon to find out how much the air inside it weighs.
C) Identifying all of the possible causes for an irregularity in the orbit of a planet concluding that they do not completely explain it and hypothesizing on that basis that there must be some other unknown cause.
D) Running a truck over a truck scale and concluding that it is carrying too much freight