Why Was the Outcome of the Democratic National Convention in 1968

Why was the outcome of the Democratic National Convention in 1968 considered to be tainted?

A) Many believed that Humphrey had won only because he leveraged support from the unaccountable party machine.
B) Many believed that McGovern won only because he entered into a corrupt bargain with McCarthy supporters.
C) Many believed that McCarthy should have won because he had the backing of labor and party elites in spite of his low level of public support.
D) Many believe that Humphrey should have won because he had the support of young activists and intellectuals who were the core of the party.