Go down the drain means be wasted or lost. 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: Go down the drain can refer to a situation involving be wasted or lost.
• Story example: A writer may use Go down the drain when describing a situation involving be wasted or lost.
• Exam example: When a sentence contains Go down the drain, choose the meaning “be wasted or lost.”