Which of the following is a correct statement about an organizing campaign?

A. During an organizing campaign, the NLRB conducts a secret-ballot election if only 30 to 50 percent of employees signed cards.

B. During an organizing campaign, only one union can appear on the ballot.

C. During an organizing campaign, a union is automatically recognized if most number of employees agree.

D. During an organizing campaign, unions determine the appropriate bargaining unit.