Which of the Following Is Said to Be a Drawback

Which of the following is said to be a drawback to Germany's tradition of strong unified parties in the Bundestag?

A) New members must serve long stints as backbenchers.
B) Party leaders can punish defiant members by giving them a low position on the party list.
C) The electorate can easily identify a party's position across a range of issues.
D) Political parties tend to adopt consistent positions over time.
E) The number of independent voters is low and voters belong to and consistently vote for the same party in Germany's parliamentary elections.