Answer No : 5 :
void setup()
{
  pinMode(8,OUTPUT);
  pinMode(2,INPUT);

}
void loop()
{
  	int signal;
  	signal=digitalRead(2);
  	if(signal==HIGH)
    {
  		tone(8,1000);  
  		delay(1000);
      	                noTone(8);
    }  	
}

Output:
Circuit