What Action Would Best Describe How a Group of Employees

What action would best describe how a group of employees can designate a union as the bargaining agent with an employer?

A) by enlisting a shop steward to provide a list of approved options for representation
B) by obtaining signatures on authorization cards from at least 30 percent of employees
C) by meeting with an employer mediator who will select an appropriate union
D) by publicly soliciting potential unions on social media and through targeted emails
E) by organizing a formal vote where at least 50 percent of workers agree on a specific union