Which of the following statement(s) is/are found to be incorrect? I. Three ancient Tamil kingdoms: Chera, Chola and Pandya: frequently involved in internecine warfare to gain regional Supremacy. II. Tamil is the oldest among the spoken and literary languages of South India and the earliest literature of this language is known as the Sangam literature. III. The Sangam literature preserves folk memory about the society and the life in South India between the third century BC and the third century AD.