To find the equivalent prefix form (or Polish Notation):
1) The given expression is in infix form i.e. fully parenthesized unambigous expression
2) Firstly,we have to make a rooted binary tree for the given expression
3) Then we have to apply Preorder Tree Traversals
4) The obtained expression would be an equivalent prefix or polish notation
On solving we can check that A is the correct answer...