4- The operation to add an entry to a stack is called a(n) a. put b. add c. push d. peek S- Given the following infix expression w+x*y/z, which one of the following is the corresponding postfix expression? d. none of the above Using the evaluatePostfix algorithm, evaluate the following postfix expression. 72+3 6- a. 15 b. 13 c. 36 d. 27