The best data structure to check whether an arithmetic expression has balanced parentheses is a

Which of the following is essential for converting an infix expression to the postfix form efficiently?

Consider the following statements:
(i) First-in-first out types of computations are efficiently supported by STACKS.
(ii) Implementing LISTS on linked lists is more efficient than implementing LISTS on an array for almost all the basic LIST operations.
(iii) Implementing QUEUES on a circular array is more efficient than implementing QUEUES on a linear array with two indices.
(iv) Last-in-first-out type of computations are efficiently supported by QUEUES.