$($a$)$ Draw the activation tree generated by executing main when val is $3.$

$($b$)$ Using a runtime stack, show the activation records generated by executing main when val is $1.$ You only need to include the old frame pointer, return address, returned value, and function argument$($s$)$; don$$t worry about temporary variables. You can expand the stack in either direction, as long as you are clear about the direction of expansion in your answer.