Select the most appropriate meaning of the underlined idiom in the given sentence.

When the miscreants saw the police they beat a retreat.

ran away

The answer is ran away.

The idiom "beat a retreat" means to withdraw or run away from a dangerous or difficult situation. In the sentence, "When the miscreants saw the police they beat a retreat," it means that the criminals ran away when they saw the police. This is because they were afraid of being caught and punished.

The other options are not correct.

• "Protested strongly" means to express disapproval or opposition in a forceful way. This is not the meaning of the idiom in the sentence.
• "Attacked fiercely" means to start fighting or attacking someone or something in a violent way. This is not the meaning of the idiom in the sentence.
• "Marched ahead" means to walk or move forward in a determined or confident way. This is not the meaning of the idiom in the sentence.