Concept:The question tests knowledge of correct English spellings. One of the given words is misspelt.Explanation:Check each word for correct spelling."Desiccation" is correctly spelled. It means removal of moisture."Descendant" is correctly spelled. It means a person descended from an ancestor."Derogatary" is incorrectly spelled. The correct spelling is "Derogatory", which means showing a disrespectful attitude."Dermatitis" is correctly spelled. It refers to a skin condition.Thus, the only misspelt word is "Derogatary".Answer:Derogatary (Option C)