(A) Cultural differences
(B) Diseases like yellow fever
(C) Engineering difficulties
(D) ** All the answers are correct.
EXPLANATIONS BELOW
Concept note-1: -In constructing the Panama Canal, American planners and builders faced challenges that went far beyond politics and engineering. The deadly endemic diseases of yellow fever and malaria were dangerous obstacles that had already defeated French efforts to construct a Panama Canal in the 1880s.
Concept note-2: -The building of the Panama Canal involved three main problems–engineering, sanitation, and organization. Its successful completion was due principally to the engineering and administrative skills of such men as John F. Stevens and Col.
Concept note-3: -On December 31, 1999, the United States, in accordance with the Torrijos-Carter Treaties, officially hands over control of the Panama Canal, putting the strategic waterway into Panamanian hands for the first time.
Concept note-4: -All three men faced innumerable challenges, including a complex bureaucracy, pressure from American politicians, and the constant threat of yellow fever and malaria, all while planning the construction and execution of the world’s largest lock canal to date.