Come of age means become mature or legally adult. 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: Come of age can refer to a situation involving become mature or legally adult.
• Story example: A writer may use Come of age when describing a situation involving become mature or legally adult.
• Exam example: When a sentence contains Come of age, choose the meaning “become mature or legally adult.”