A golden opportunity means a very good chance to do something valuable. 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 golden opportunity can refer to a very good chance to do something valuable.
• Story example: A writer may use A golden opportunity when describing a very good chance to do something valuable.
• Exam example: When a sentence contains A golden opportunity, choose the meaning “a very good chance to do something valuable.”