Final answer:
The area of water affected by the Deepwater Horizon can be calculated using satellite imagery and GIS tools, which are effective due to the visibility of oil on the water's surface.
Step-by-step explanation:
To calculate the area of water affected by the Deepwater Horizon oil spill, the correct option is B, by using satellite imagery and GIS tools. Satellite imagery provides a comprehensive view of the oil spill's extent on the water's surface, and GIS tools are used to analyze and estimate the total area affected. This method is effective because crude oil is immiscible with and less dense than water, allowing it to be visible on the surface, making satellite imagery suitable for measuring the spatial extent of the spill.