Look at the following program and answer the question that follows it. 1 // this program displays my gross wages. 2 // i worked 40 hours and i make $20.00 per hour. 3 #include 4 using namespace std; 5 6 int main() 7 { 8 int hours; 9 double payrate, grosspay; 10 11 hours = 40; 12 payrate = 20.0; 13 grosspay = hours * payrate; 14 cout < < "my gross pay is $" < < grosspay < < endl; 15 return 0; 16 } which line(s) in this program cause output to be displayed on the screen?