Concept:A spelling mistake occurs when a word is not written according to its standard dictionary form.Explanation:The word "Conflagaration" is misspelled. The correct spelling is "Conflagration", which means a large destructive fire. Options A, B, and D are spelled correctly. "Convalescence" means recovery time after illness. "Obsequious" means overly submissive. "Reticent" means reserved or quiet.Answer:C. Conflagaration