PLEASE HURRY! I only have 30 minutes for these questions. thank you!

Following is an incorrect pseudocode for the algorithm which is supposed to determine whether a sequence of parentheses is balanced: declare a character stack while ( more input is available) read a character if ( the character is a) push it on the stack pop a character off the stack print "unbalanced" and exit else if ( the character is a ')' and the stack is not empty) else print "balanced" Which of these unbalanced sequences does the above code think is balanced? COmO Consider the implementation of the stack using a partially-filled array. What goes wrong if we try to store the top of the stack at location (O] and the bottom of the stack at the last used position of the array? Both peek and pop would require linear time The stack could not be used to evaluate postfix expressions. The stack could not be used to check balanced parentheses. Both push and pop would require linear time. Assume that the operators +,-, ../ are left associative. The order of precedence (from highest to lowest) is+,-The postfix expression corresponding to the infix expression a +bc-d e/f is a bc / def abc + de /f- abc + de'f /