While Presidential Nominees Often Ignore Their Parties' Platform and Promote

While presidential nominees often ignore their parties' platform and promote their own themes and issue stances instead, platforms still serve as:

A) something productive for delegates to work on at national conventions, besides campaign signs.
B) a means of quieting disgruntled factions of the party, to keep them from rebelling or leaving to form third parties.
C) a means to co-opt the ideas and supporters of third parties or independent candidates.
D) "treaties" of a sort, in which various party factions can state their terms for supporting their nominees.