Smoothing and Accomodating is same so there can be removed. Compromising is Lose - Lose situations where both parties give up something however, it doesnt look like case here.

I think Answer should be Collaborating since functional manager moving resource to High Severity Project (parties agrees on view point).  

When you such situation first option you would be looking for is confronting (problem solving) else next best option is 'Compromising', so select the the best out of the lot. While compromising you might have struck a deal with fucntional manager to get something out of this situation.

FYI...Please remember it is matrix organziation where resources are reporting to fucntional manager not project manager, so manager doesn't have any control on resources except assigning the tasks and getting the work done. The team building also would be difficult situation.

Regards

CN Patil