Use the excerpt to answer the question- Congress has a split personality. On the one hand, it is a lawmaking institution and makes policy for the entire nation. In this capacity, all the members are expected to set aside their personal ambitions and perhaps even the concerns of their constituencies. Yet Congress is also a representative assembly, made up of 535 elected officials who serve as links between their constituents and the National Government. The dual roles of making laws and responding to constituent's demands forces members to balance national concerns against the specific interests of their States or districts.
-James M. Burns, et al., Government by the People

What is the best summary of this quotation?

a
Representatives and senators should spend most of their time drafting and passing new laws.
b
Members of Congress must balance the interests of their constituencies along with national concerns.
c
The primary purpose of Congress is to serve the interests of the American people.
d
It is impossible for representatives and senators to balance their roles at work along with their home lives.