This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
[{'content': 'All are true regarding DDT, Except \nSelect and explain. \nA. It acts as neurotoxin, B. It is primarily a contact poison, C. It does not cause immediate death, but it takes several hours to kill, D. It has repellent action on insects', 'role': 'user'}, {'content': 'Answer: D \nExplanation: DDT (Dichloro diphenyl trichloroethane)It was first synthesized by a German chemist, Ziedler.Its insecticidal action was described by Paul Muller.It is primarily a contact poison.It acts on the nervous system of insects.It takes several hours to kill the insect.The residual action of DDT may last as long as 18 months.It has no repellent action on insects.As a residual spray, DDT is applied at a dosage of 100-200 mg/ sq. foot area.The formulation of choice is a 5 % suspension, 5-10 % strength for the control of lice, fleas, ticks, and bugs.', 'role': 'assistant'}]