Step 1: Understanding the Concept
This question asks to identify the archaeological site with the earliest evidence of agriculture (barley and millets) in the Indian subcontinent, specifically dating back to the 7th millennium BCE (c. 7000-6001 BCE). This time frame corresponds to the Neolithic period.
Step 2: Analyzing the Sites
(A) Mehargarh: Located on the Kacchi Plain of Balochistan, Pakistan, Mehargarh is one of the most important Neolithic sites in South Asia. Archaeological evidence from its earliest levels (Period I) dates back to around 7000 BCE and shows the cultivation of wheat and barley, along with the domestication of animals.
(B) Kalibangan, (C) Harappa, and (D) Mohanjodaro: These are all major urban centers of the Indus Valley Civilization (or Harappan Civilization). This civilization flourished during the Bronze Age, roughly from 3300 BCE to 1300 BCE, which is much later than the 7th millennium BCE.
Step 3: Final Answer
Mehargarh is the correct answer as it represents the pre-Harappan, Neolithic period where the first evidence of agriculture in the region is found.