Reverse polish notation is postfix notation ,so we have postfix form expression
Firstly we have to convert POSTFIX -> INFIX
Which can be converted as given in my reference answer https://gateoverflow.in/8408/gate2015-3_12
Infix - > (((3*4)-5)^2)-((6*7)+1))
So new order is Root Right Left
- ((6*7)+1) (((3*4)-5)^2)
-((*76)+1))(((*43)-5)^2)
-(+1*76)((-5*43)^2)
-+1*76^2-5*43
so option c is right