The answer is b. Landscapes with coasts will raise the chances of waterspouts.
Waterspouts are generally formed over water, and are more common in coastal areas where there is a temperature difference between the warm water and the cooler air above. The warm water heats the air above it, causing it to rise and cool, which can create a column of rotating air. If the conditions are right, this rotating air column can develop into a waterspout.
Coastal landscapes can also create other conditions that are favorable for waterspouts, such as the presence of sea breezes and other wind patterns that can contribute to the formation of rotating air columns. However, the amount of rainfall in a given landscape is not generally a major factor in the formation of waterspouts.