Consider the following code:

x $=9$

sum $=0$

while x $<19$:

x $=$ x $+1$

$$ num $=$ int$($input$("$Enter a number: $"))$

$$ sum $=$ sum $+$ num

$$ print$($str$($x$)+"$: $"+$ str$($num$)+"$ Total: $"+$ str$($sum$))$

Which of the following is the loop control variable?