<prompt> Serum sickness is:Type 1 hypersensitivity reactionType 2 hypersensitivity reactionType 3 hypersensitivity reactionType 4 hypersensitivity reaction  <response>: Ans: C. Type 3 hypersensitivity reactionRef: Robbins 9e p207Serum sickness is the prototype of a systemic immune complex disease or type III hypersensitivity reaction.Immune Complex--Mediated Type III Hypersensitivity:Acute serum sickness is the prototype of a systemic immune complex disease; it was once a frequent sequela to the administration of large amounts of foreign serum e.g., serum from immunized horses used for protection against diphtheria. 