Asurgical team performing open-heart surgery on a patient is an example of a (n) group.

The answer to this question should be: formal group

A formal group is made by some people that were made to achieve a certain goal. This group mostly have a good structure and hierarchy. They work in a professional way so it might have some legal responsibility that was regulated by law.
In this case, the team performing open-heart surgery should have a leader that will determine what will they do when some options appear. Every member also has different roles and capability. They also have shared responsibility about the patient well being. 

The answer is d have a nice day