The correct option is A I, II & III
The incorrect statements are I, II and III.
Oviparous mammals lay eggs and have mammary glands to nourish young ones. Eg: Platypus.
The skin in mammals is provided with sweat glands and sebaceous glands. The sebaceous glands secrete an oily secretion called sebum that keeps the skin moist.
Heterodont dentition means having different types of teeth. This is a feature of mammals. The different types of teeth of mammals include incisors, canines, premolars and molars.
Statement IV is correct. The presence of pinna is the characteristic feature of mammals.