A red herring means something that distracts attention from the real issue. This answer is correct because the expression has a fixed figurative meaning in English. In an SSC idiom question, students should match the whole phrase with its accepted meaning rather than translate each word separately.

• Classroom example: A red herring can refer to a situation involving something that distracts attention from the real issue.
• Story example: A writer may use A red herring when describing a situation involving something that distracts attention from the real issue.
• Exam example: When a sentence contains A red herring, choose the meaning “something that distracts attention from the real issue.”