In the converged conference MCU central networking mode, what method does the eSpace PC support to join the conference directly with the chairman authority? () (multiple choice)

In the converged conference MCU central networking mode, what method does the eSpace PC support to join the conference directly with the chairman authority? () (multiple choice)
A . Key in the conference list
B . Dial in
C . Join by email link
D . Invitation from outside

Answer: A,B,C