What Are Political Parties Required to Do When Differences Exist

What are political parties required to do when differences exist within the party?

A) ​moderate between intraparty differences
B) ​allow party leaders absolute discretion in selecting party positions
C) ​select only the positions leaders feel can enable them to win elections
D) ​select only the positions leaders feel most strongly about, even if it costs them elections
E) Sometimes, parties have performed these functions well, and sometimes they have not.