Which of the following Python functions is correctly defined and adheres to the principles of clear and efficient code design?

Which of the following Python functions is correctly defined and adheres to the principles of clear and efficient code design?

def calculate$\_$sum$($a$,$ b$)$:

$$ return a $+$ b

def calculate$\_$sum$($a$,$ b$)$

$$ return a $+$ b

def calculate$\_$sum$($a$,$ b$)$

$$ result $=$ a $+$ b

$$ print$($result$)$

def calculate$\_$sum$($a$,$ b$)$

$$ result $=$ a $+$ b

$$ result

elif x $==5$:

$$print$($x is equal to $5)$

else:

$$print$($x is greater than $5)$

x is equal to $5.$

No output will be produced.

x is greater than $5.$

x is less than $5.$