. A village has a total of 100 under-five children. The coverage with measles vaccine in this age group is 60%. Following the occurrence of a measles case in a child after a visit outside, twenty six children developed Of measles is - measles. The secondary attack rate: (A) 0.25, (B) 0.4, (C) 0.5, (D) 0.65
Answer is D. None