Answer:
The Matching Principle
Step-by-step explanation:
The Matching Principle of accounting holds that revenues should be matched with expenses. Hence the name.
This is to say, that revenues should only be recognized when the associated expenses with those revenues have been spent.
For example, in numeral a), we can see that Norfolk Southern Corporation recieved cash in advance, but it only recognized revenue once it had performed the services associated with that cash collection.