Get down to brass tacks means begin discussing the most important practical details. 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: Get down to brass tacks can refer to a situation involving begin discussing the most important practical details.
• Story example: A writer may use Get down to brass tacks when describing a situation involving begin discussing the most important practical details.
• Exam example: When a sentence contains Get down to brass tacks, choose the meaning “begin discussing the most important practical details.”