Answer :
Answer: Routine problem solving
Explanation: In simple words, routine problem solving refers to the straight and simple problems that usually do not require any creativity to get solved. These problems are solved by following a predetermined set path of guidelines.
In the given case, Mary has been dealing with Gibson for many years, that is, they must be having strong business relations. Also she will be full aware of the operations of Gibson's business framework.
Hence Mary would employ routine problem solving.