Given the following Python script:

def doubler$($x$)$:

return x $*2$

def halfer$($x$)$:

return x $/2$

def area$\_$of$\_$square$($x$)$:

return x $**2$

def my$\_$func$($x$)$:

area$1=$ area$\_$of$\_$square$($x$)$

y $=$ doubler$($x$)$

area$2=$ area$\_$of$\_$square$($y$)$

return area$2-$ area$1$

def multiplier$($x$,$ y$)$:

return x $*\}$

my$\_$func$(3)$

How many functions are defined in the above code?

$2$

$4$

$3$

$5$