Who led the most celebrated oceanographic expedition, voyage of the Challenger?

Correct option is A

Correct Answer: (a) C. W. Thomson
Explanation:
→ Sir Charles Wyville Thomson was the chief scientist of HMS Challenger (1872–1876), leading the foundational global oceanographic expedition.
→ The voyage systematically collected data on ocean depth, temperature, biology and sediments.
Information Booster:
→ Challenger findings established oceanography as a scientific discipline and produced an extensive multi-volume report.
Additional Information (Other Options):
(c) M. F. Maury: earlier pioneer of naval oceanography (U.S.).
(d) Edward Forbes: important naturalist but not leader of Challenger.
(b) J. Armstrong: not related here.