Insecticide of choice to prevent kala-azar-
High-Yield Explanation
Ans. is 'a' i.e., DDT * Resistance to DDT has not been demonstrated in sandflies* A single application of DDT or lindane has been found effective in reducing sandflies.* DDT residue may remain effective for a period of 1 to 2 years and lindane only for a period of 3 months.