About Audio in and Out MAIN Port and AUX Port

About audio in and out MAIN port and AUX port, which statement is true ( ) (select two answers)

A) the MAIN port and AUX port don't have echo canceller function
B) the Main interface has echo canceller function, but cannot hear your own voice
C) Aux interface does not have echo cancellation feature, but you can hear your own voice
D) Both interfaces have echo cancellation feature body