A chip on one's shoulder means a habit of feeling angry or easily offended because of past unfairness. 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 chip on one's shoulder can refer to a habit of feeling angry or easily offended because of past unfairness.
• Story example: A writer may use A chip on one's shoulder when describing a habit of feeling angry or easily offended because of past unfairness.
• Exam example: When a sentence contains A chip on one's shoulder, choose the meaning “a habit of feeling angry or easily offended because of past unfairness.”