Difference between international and national flight​

A national flight is one that stays within the same country while an international flight is one that arrives in a different country. If you live in the US, then a domestic flight would be one between one US state to another, or even within the same state

I'm pretty sure it's c. extremely gradual but not 100% sure though.

Answerscripps institution of oceanography; i believe this is correct plz check first good luck;