Step 1: Context of Indus Valley excavations.
The Indus Valley Civilization was first discovered in 1921 (Harappa) and 1922 (Mohenjo-Daro). These excavations revealed one of the world’s earliest urban civilizations. Later, more sites were discovered in Gujarat and Rajasthan.
Step 2: Excavation at Lothal.
Lothal, located in present-day Gujarat, was excavated under the leadership of S.R. Rao. It revealed a dockyard, bead-making factories, and advanced town planning. The excavation began in 1955.
Step 3: Elimination of options.
- (A) 1921: This refers to Harappa excavation, not Lothal.
- (B) 1925: Mohenjo-Daro excavation, not Lothal.
- (C) 1946: Refers to discovery of other Indus sites like Chanhudaro.
- (D) 1955: Correct year when S.R. Rao started excavation at Lothal.
Conclusion: The excavation at Lothal began in 1955.