The correct option is A Alexander the Great's army
The Vedic period or Vedic age ( c. 1500 – c. 500 BCE), is the period in the history of the northern Indian subcontinent between the end of the urban Indus Valley Civilisation and second urbanisation which began in the central Indo-Gangetic Plain. After Alexander invaded India, Megasthenes, who accompanied his army, wrote in Indica, the first detailed reports of ancient Vedic culture and Mauryan empire. Hence, Option A is incorrect. Since the rest of the ethnicities came to India after Alexander's invasion, their accounts are recorded much later. Hence, these are incorrect.