This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical Entomology, Subject name: Social & Preventive Medicine
All are true about DDT except 
Select and explain. 
A. Kills mosquito immediately, B. Insecticidal propeies discovered by Paul H. Muller, C. Residual action lasts for 18 months, D. Contact/ nerve poison
A: Kills mosquito immediately
Answer: A: Kills mosquito immediately 
Explanation: DDT takes several hours to kill mosquito Dichloro Diphenyl trichloroethan (DDT) First synthesis by - ZIEDLER Propeies by - Paul muller (Nobel Prize) No repellant action Takes several hours to kill Residual action lasts for 18 months Most active form of DDT - PARA - PARA ISOMER Mode of action - At as a contact/Nerve poison - Inhibits Acetylcholinesterase