Why did people wear powdered wigs ?

Which events are correlated but do not necessarily have a causal relationship?

Powers of states the first letter of the answer is r.

Which source would best a historian understand the effect of the great chicago fire on families? a. a biography of a chicago family displaced by the fire b. a letter from a grandmother in new york to her family in chicago c. a newspaper editorial about families who were displaced d. an oral history dictated by an adolescent who fled the fire