One Important Difference Between an Integrating Role and a Liaison

One important difference between an integrating role and a liaison role is:

A) the liaison role is a formal position inside one of the departments and the integrating role is informal.
B) the integrating role is a formal position inside one of the departments and the liaison role is informal.
C) the liaison role is a more complex integrating mechanism.
D) the integrating role is located outside the departments that are being coordinated.