Which of the following is an example of operator overloading?

Question $12$ options:

classSumofPairs:def$\_\_$init$\_\_($self$,$num$1,$num$2)$:self.num$1=$num$1$self.num$2=$num$2$def$\_\_$str$\_\_($self$)$:return$($f$\text{'}\{$self$.$num$1\}\{$self$.$num$2\}\text{'}))$

classSumofPairs:def$\_\_$init$\_\_($self$,$num$1,$num$2)$:self.num$1=$num$1$self.num$2=$num$2$def$\_\_$add$\_\_($self$,$other$)$:num$1=$self.num$1+$other.num$1$num$2=$self.num$2+$other.num$2$returnSumofPairs$($num$1,$num$2)$

classSumofPairs:def$\_\_$init$\_\_($self$,$num$1,$num$2)$:self.num$1=$num$1$self.num$2=$num$2$def$\_\_$add$\_\_($self$,$other$)$:num$1=$self.num$1+$other.num$1$num$2=$self.num$2+$other.num$2$

classSumofPairs:def$\_\_$init$\_\_($self$,$num$1,$num$2)$:self.num$1=$num$1$self.num$2=$num$2$def$\_\_$add$\_\_()$:num$1=$self.num$1+$other.num$1$num$2=$self.num$2+$other.num$2$returnSumofPairs$($num$1,$num$2)$