Choose the correct variant1. one of many telephone lines connected to a central system in a large building, which all have different numbers Blank 1 dial toneCall me back, please.extensionpound keyHold on, please.hang up the phoneI think I have the wrong number. 2. the sound you hear when you pick up the telephone that lets you know that you can make a call Blank 2 dial toneCall me back, please.extensionpound keyHold on, please.hang up the phoneI think I have the wrong number. 3. the button on a telephone that has the symbol (#) on it Blank 3 dial toneCall me back, please.extensionpound keyHold on, please.hang up the phoneI think I have the wrong number. 4. When you call somebody by mistake you say Blank 4 dial toneCall me back, please.extensionpound keyHold on, please.hang up the phoneI think I have the wrong number. 5. When you want somebody to return your call you say Blank 5 dial toneCall me back, please.extensionpound keyHold on, please.hang up the phoneI think I have the wrong number. 6. When you finish the telephone conversation you Blank 6 dial toneCall me back, please.extensionpound keyHold on, please.hang up the phoneI think I have the wrong number. 7. When you ask somebody on the phone to wait until the person they want to talk to is available you say Blank 7 dial toneCall me back, please.extensionpound keyHold on, please.hang up the phoneI think I have the wrong number.