通常耐用消费品是指价值较大、使用寿命相对较长的家用商品，包括汽车、计算机、家具、健身器材、乐器等。( )

What is the MOST important thing you should do before transmitting on a marine radio? （）

A.Ask for permission

B.Record the time in your radio log

C.Press the push to talk button three times

D.Monitor the channel to insure that it is clear