Solution:Based on the variation of tools, the Palaeolithic age is divided into three periods- 1. Early Palaeolithic - Code tools (Handkuthar, Khandak, Vidarni),
2. Middle Palaeolithic - Plaque tools and
3. Upper Palaeolithic - Takshini and scraper tools.
Therefore, it is clear that the question has been asked in relation to stone tools which first appeared in the Palaeolithic period. Staff Selection Commission, in its previous answer-sheet, had considered the answer to this question as the Neolithic period. However, in the revised answer-sheet, the answer to this question is considered to be the Palaeolithic period, which is true.