The correct option is D Population growth is exponential
Growth patterns of population are classified into exponential growth and logistic growth based on the nature of growth and specific requirement.
In exponential growth, population density of an organism increases rapidly in an exponential way but stops abruptly due to various factors such as environmental resistance, end of the breeding phase etc.
The population growth of an insect species is exponential because its growth increases explosively and stops abruptly during the rainy season. Growth of the insects stops because environmental factor is not favourable for its breeding.
Growth pattern of the insect population is not logistic because its initial phase is not a lag phase which later accelerates and decelerates.