Many macromolecular complexes in the cell contain scaffold proteins. What do these proteins do that benefits the cell?

A) They can enhance the rate of critical cellular reactions.
B) They can hold the many subunits of a large complex together.
C) They can confine and concentrate a specific set of interacting proteins to a particular cellular location.
D) They can provide a large macromolecular complex with either flexibility or rigidity.
E) All of the above.