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 is easily able to identify a party's position across a range of issues.
D) The parties tend to adopt consistent positions over time.
E) None of the above.