From 1836 to 1936, Democratic Nominating Conventions Were Longer and More

From 1836 to 1936, Democratic nominating conventions were longer and more contentious because:

A) As the dominant political party, their nomination was more important.
B) The Democratic Party allowed voters to elect the convention delegates, preventing party insiders from selecting a unifying candidate .
C) The Democratic nominee was required to garner at least two-thirds of convention delegates to secure the nomination.
D) This statement is false: Democratic conventions were actually less contentious because they were based on majority rule.