A clean slate means a fresh start without past mistakes being counted. 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 clean slate can refer to a fresh start without past mistakes being counted.
• Story example: A writer may use A clean slate when describing a fresh start without past mistakes being counted.
• Exam example: When a sentence contains A clean slate, choose the meaning “a fresh start without past mistakes being counted.”