Explanations:Kolkata, the capital city of West Bengal, is known for its susceptibility to flooding, particularly in areas with old canals. The city's geography and historical infrastructure play a significant role in its flood-prone nature. The old canals in Kolkata were constructed during the colonial era to manage water flow and drainage. However, these canals are often inadequate for modern flood control due to their age and the increasing urbanization of the city.
The old canals in Kolkata are typically located in low-lying areas, which are more prone to flooding during heavy rains. These canals were designed to handle a certain volume of water, but with the increase in urban development and the consequent reduction in natural drainage areas, the canals are often overwhelmed during monsoon seasons. This leads to water accumulation and flooding in the surrounding areas.
It is important to understand the historical context of these canals and their role in the city's infrastructure. The colonial-era canals were part of an early attempt to manage water flow and drainage in the city. However, as the city has grown and developed, the infrastructure has not kept pace with the increasing population and urbanization. This has resulted in the old canals becoming a significant factor in the city's flooding issues.
Other options such as houses on stilts and mansions on hills are modern adaptations to prevent flooding. Houses on stilts are built above the flood level to avoid water accumulation, while mansions on hills are naturally elevated and less susceptible to flooding. The ocean, while a significant body of water, does not "flood" Kolkata in the context of the question. The city's flooding issues are primarily related to its low-lying areas and inadequate drainage systems.
In summary, the old canals in Kolkata are the correct answer because they are a significant factor in the city's flooding issues. These canals, built during the colonial era, are often inadequate for modern flood control and are located in low-lying areas that are prone to water accumulation during heavy rains.