Final answer:
The lookouts on the Titanic were in the crow's nest, which allowed them to see farther over the horizon on a spherical Earth. The Earth's curvature makes higher vantage points advantageous for sighting distant objects at sea, a fact well understood by mariners like Columbus.The correct option is A.
Step-by-step explanation:
When the Titanic hit the iceberg, the lookouts were in Position A: In the crow's nest, high up on the mast. The role of a lookout on seafaring vessels, historically, was to observe any hazards or other ships in the vicinity. The crow's nest provided a higher vantage point which, considering the Earth's curvature, allowed lookouts to see farther over the horizon than they would from the lower decks. On a spherical Earth, the higher one's position above sea level, the farther one can see. If the Earth were flat, there would not be as significant an advantage to posting lookouts high up, since visibility would not be affected by the planet's curvature.
To better understand how this works, consider a simple diagram of a ship at sea: as a ship travels away from the observer on a spherical Earth, the lower parts disappear first due to the curvature, leaving only the mast visible for a period of time. The same curvature explains why lookouts from higher points like a masthead can see further. Columbus and other mariners were aware of these navigational truths, which helmed their understanding of the Earth's shape.