What is the infix $($in$-$order$)$ representaion of the following postfix $($post$-$order$)$ expression?

$x12+z27y+42**l+,$ where $x,y,$ and $z$ are variables

Use a stack to find the infix expression as follow:

For each symbol in the postfix expression:

If it is an operand $($variable or constant$),$ push it onto the stack.

If it is an operator, pop the required number of operands from the stack, where the top is the second operand.

Apply the operator on both operands, and push the result back onto the stack.

a$.x+12+\frac{z}{27}+y**42$

b$.$

$x+12+\frac{z}{(27+y)**42}$

c$.\frac{x+12+z}{27+y**42}$

d$.x+\frac{12+z}{27+y**42}$