Final answer:
The main reason for proposing offshore wind turbines is B)the more constant and higher average wind speeds over oceans, leading to more efficient and reliable electricity generation, as well as a reduced environmental impact compared to land-based installations.
Step-by-step explanation:
The primary reason why wind turbines are proposed to be offshore is that the wind resource over the oceans is more constant and has higher average wind speeds than on land. This consistent and stronger wind resource translates to more efficient electricity generation and the ability to generate power more reliably. Furthermore, offshore wind farms tend to have a smaller environmental impact compared to land-based installations. Although wind turbines can be a source of additional income for landowners and have a small physical footprint relative to their energy output, concerns such as their visibility, noise, and the threat they pose to birds and bats, particularly along migratory paths, can be mitigated more effectively when they are located offshore.
While installations of wind turbines on land can contribute significantly to local economies and have relatively low environmental challenges, the vast potential and lower visibility of offshore wind farms make them a compelling alternative. Offshore setups avoid many of the aesthetic and ecological issues associated with land-based wind turbines, though they still face challenges with respect to construction impacts and potential interference with marine life, which are subjects of ongoing research.