The Reason Why Unions Generally Prefer a Card Count to a Vote

The reason why unions generally prefer a card count to a vote as a means of establishing certification is

A) because it's what they're used to.
B) because a card count allows unions to harass and intimidate workers into joining.
C) voting is costly.
D) with a card count,the labour board doesn't have to get involved.
E) because if there's a vote,employers can get involved and influence the process.