Which statement about the following JavaScript code is true?

let greeting $=$ "Happy birthday!";

if $($ageAtBirthday $<6)\{$

greeting $+="$ You are a cute little kid.";

$\}$ else if $($ageAtBirthday $<40)\{$

greeting $+="$ Have lots of fun!";

$\}$ else if $($ageAtBirthday $===16)\{$

greeting $+="$ You are old enough to drive.";

$\}$ else $\{$

greeting $+="$ You are over the hill!"

;

$$