$.$ What is the result of evaluating the following postfix expression?

$57+62-*$

Hint: postfix evaluates the operands that appear before their operators $($evaluated from L$->$R$).$

$[1]0$

$[2]12$

$[3]48$

$[4]$ too few operands

$[5]$ None of these is correct.

$7.$ What is the result of evaluating the following postfix expression?

$34+2*7/$

$[1]0$

$[2]2$

$[3]14$

$[4]$ too few operands

$[5]$ None of these is correct.