Binary mixtures that have the same composition in liquid and vapour phase are known as azeotropes. These solutions boil at a constant temperature. The two types of azeotropes are minimum boiling azeotropes and maximum boiling azeotropes. Water-nitric acid is a maximum boiling azeotrope and water-ethanol is a minimum boiling azeotrope. The options (i) and (iv) are examples of ideal solutions, hence they cannot be azeotropes.

Hence the correct answers are (ii) and (iii).