The correct options are
B Based on the severity of danger due to cyclone, Tamil Nadu is divided into five zones: very-high, high, medium, low, and very-low risk zones.
C Nagapattinam is in high-risk zone.
D During the retreating monsoon, there is higher risks of cyclone hitting the coasts.
According to the United Nation Office of Disaster Risk Reduction, Disaster Risk Reduction is the concept and practice of reducing disaster risks through systematic efforts to analyse and reduce the causal factors of disaster.
During the retreating monsoon, there are higher risks of a cyclone hitting the coasts.
Based on the severity of danger due to cyclone, Tamil Nadu is divided into five zones: Very-high, high, medium, low, and very-low risk zones. Nagapattinam, Tiruvallur, Tiruvarur, etc. are high-risk zone.