Step 1: Identity.
Francis Buchanan (later known as Francis Buchanan-Hamilton) was a Scottish physician, botanist, and geographer.
Step 2: Contributions.
He served as a doctor in the East India Company and conducted extensive surveys in Bengal, Mysore, and other regions of India. His surveys included geography, agriculture, flora, fauna, and social practices.
Step 3: Elimination.
- (A) A doctor: Correct, as he was primarily a physician by training.
- (B) A landlord: Incorrect.
- (C) A businessman: Incorrect, though he worked under the Company.
- (D) Governor: Incorrect, he was never a political governor.
Step 4: Conclusion.
Thus, Francis Buchanan was a doctor by profession and a surveyor by contribution in India.