Blow hot and cold means keep changing one's opinion or attitude. 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: Blow hot and cold can refer to a situation involving keep changing one's opinion or attitude.
• Story example: A writer may use Blow hot and cold when describing a situation involving keep changing one's opinion or attitude.
• Exam example: When a sentence contains Blow hot and cold, choose the meaning “keep changing one's opinion or attitude.”