Answer:
b.When two or more candidates seek to run for the same office from the same party.
Explanation:
A nomination contest consists of a procedure in which a political party selects its candidate for the following general election (usually 3-6 months before it or in the 1st week of an election campaign). The local riding association of this party carries out this contest, and sometimes the president of the party chooses to avoid this step by directly appointing the candidate he/she considers the best.