In Considering the Criteria for an Ideal Voting System,the Idea

In considering the criteria for an ideal voting system,the idea of an irrelevant alternative refers to:

A) when an option is added to a vote and is unrelated to the issue being voted on.
B) different voting methods that could alternatively be used, but would not change the outcome.
C) when an option is added to a vote and has no realistic chance of winning.
D) different voting methods that could alternatively be used, and could change the outcome.