All of the following statements concerning parties in American democracy are true EXCEPT this:

a. They help provide a linkage between voters and elected officials.
b. They help to unify a fragmented government.
c. They provide a voice for the opposition to official government policy.
d. They have become an impediment to the operation of modern democracy.
e. They differ from interest groups in that they seek to nominate and elect officials to public office.

d. They have become an impediment to the operation of modern democracy.