function chapter Somebody can explain me why the output isnt 12

Question

Somebody can explain me why the output isnt 12
thank you
https://www.sololearn.com/Play/JavaScript
What is the output of the following expression?
function multNmbrs(a, b) {
var c = a*b;
}
multNmbrs(2, 6);

Answer 1

Doesn't really return or alert anything...

Answer 2

Nothing

Answer 3

Nothing

Answer 4

Exactly what Kuba said

function multNmbrs(a,b){
var c = a*b;
return c;
}
mulNmbers(2,6);

now this function would return 12