A hidden agenda means a secret plan or motive. 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 hidden agenda can refer to a secret plan or motive.
• Story example: A writer may use A hidden agenda when describing a secret plan or motive.
• Exam example: When a sentence contains A hidden agenda, choose the meaning “a secret plan or motive.”