Final answer:
The Negrito or Adivasi people are considered the very first inhabitants of ancient India, eventually categorized as the Dalits or 'untouchables' in the hierarchical structure of the Hindu caste system developed by the Aryans.
Step-by-step explanation:
The Negritos, also known as the Adivasis in India, are traditionally considered among the very first inhabitants of ancient India. They were likely the descendants of the original populations of South India before the arrival of the Aryans, according to historical records. The Hindu caste system, developed by the Aryans after their arrival in India around 1500 BCE, categorized society into four main groups: Brahmins, Kshatriya, Vaishya, and Shudras, with the Dalits or 'untouchables' being outside of this system. This rigid social structure was perpetuated by religious sanctions and identified individuals with their inherited status from birth to death. Historical records link the Negritos or Adivasis with the Dalits or 'untouchables', viewed hierarchically below the four-tiered caste system. As such, the correct answer to the question is that the people of the Negrito or the Negro caste were considered the very first inhabitants of ancient India (a).