If you enter $123,$ when you run this program, what will be the output?

#include

using namespace std;

int main$()$

$\{$

$//$ Prompt the user to enter three numbers

double number$1,$ number$2,$ number$3$;

cout $<<$ "Enter three numbers: $"$;

cin $>>$ number$1>>$ number$2>>$ number$3$;

$//$ Compute average

double average $=($number$1+$ number$2+$ number$3)/3$;

$//$ Display result

cout $<<$ average $<<$ endl;

return $0$;

$\}$

A$.1$

B$.2$

C$.3$

D$.4$