The correct option is R.E.M. Wheeler.
Explanation
The evolution of archaeological methodology in India saw a significant shift in the mid-20th century, moving from mechanical excavation techniques to more scientific, context-aware methods under the leadership of R.E.M. Wheeler.Detailed Analysis:
- R.E.M. Wheeler (Correct): Appointed as the Director-General of the Archaeological Survey of India (ASI) in 1944, Wheeler was an ex-army brigadier. He is credited with bringing military precision and discipline to the practice of archaeology. Most importantly, he recognized that excavating along uniform horizontal lines (as done previously) distorted the historical record. He introduced the method of stratigraphy-excavating layer by layer following the natural soil deposition-to accurately correlate artifacts with their specific time periods.
- Alexander Cunningham (Incorrect): He was the first Director-General of the ASI (mid-19th century). His main interest lay in the archaeology of the Early Historic period (c. 6th century BCE-4th century CE) and using Chinese pilgrim accounts to locate Buddhist sites. He did not use modern stratigraphic methods.
- John Marshall (Incorrect): As the Director-General during the discovery of the Indus Valley Civilization (1920s), Marshall oversaw the excavations at Harappa and Mohenjo-Daro. However, he tended to excavate in regular horizontal units, ignoring the stratigraphy of the site. This caused artifacts from different layers (and thus different time periods) to be grouped together, resulting in the loss of valuable contextual information.
- Daya Ram Sahni (Incorrect): He is famous for discovering the seals at Harappa in the early 1920s, working under John Marshall's general leadership. He followed the methodologies prevalent at that time.
Key Takeaway:
R.E.M. Wheeler revolutionized Indian archaeology by replacing mechanical horizontal excavation with stratigraphic excavation, ensuring that artifacts were recorded within their correct geological and chronological layers.