Seasonal trends is shown by-: (A) Varicella, (B) Polimyelitis, (C) Malaria, (D) Measles
Answer is A. .seasonal trend is a well known characteristic of many communicable diseases such as varicella,cerebrospinal meningitis,upper respiratory infections,malaria etc.varicella is usually at its height in early spring and so is measles. ref:parks textbook ,22nd edition,pg no 62