Explanation:

Daya Ram Sahni was an Indian archaeologist who played a crucial role in the discovery and excavation of the Harappa site, one of the key settlements of the Indus Valley Civilization.

Excavation of Harappa (1921)

• In 1921, under the direction of John Marshall, the then Director-General of the Archaeological Survey of India (ASI), Daya Ram Sahni led the first systematic excavation at Harappa, located in present-day Pakistan.
• His work provided the first solid evidence of an ancient, advanced civilization in the Indian subcontinent, later named the Indus Valley Civilization (IVC).
• The excavation revealed well-planned cities, drainage systems, and advanced craftsmanship, indicating a highly developed urban culture.

Other Archaeologists Involved in IVC Discoveries

• Rakhal Das Banerji (B) – Excavated Mohenjo-Daro in 1922.
• Ernest J.H. Mackay (C) – Conducted further excavations at Mohenjo-Daro in the 1920s and 1930s.
• B.K. Thapar (D) – Worked on later excavations of Indus Valley sites but not Harappa.

Thus, the correct answer is (A) Daya Ram Sahni, as he was the first to excavate Harappa in 1921.