Tropical storms, humidity, and frequent rainfall.
Plessy v Ferguson was a landmark case and was a United States Supreme Court decision to uphold the laws that kept segregation, under the phrase "separate but equal". This regarded public facilities for the most part including buses, bathrooms and water fountains. This was brought from the Committee of Citizens in New Orleans, so this was applied across the board in Louisiana.
In urban areas, there are more people, therefore not a lot of farmland. (that eliminates C) If city buildings don't allow flood waters to recede, that could be dangerous in many ways. (So A is still a reasonable answer) If most cities are built in flood zones, there should be some form of shelter if houses aren't safe. Pollutants and diseases being carried in water are already dangerous, but easier to spread with rapid flood waters that are sweeping everywhere. So your best answer would be either A or B.
