Know no bounds means have no limits. 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: Know no bounds can refer to a situation involving have no limits.
• Story example: A writer may use Know no bounds when describing a situation involving have no limits.
• Exam example: When a sentence contains Know no bounds, choose the meaning “have no limits.”