Give meaning of the underlined idiom as used in the following sentence:
He requested her to reconsider the decision but she put her foot down.

The idiom 'put foot down' means to use one's authority to stop something from happening. Option A is incorrect because putting one's foot down implies disagreement with the process. Option B is not very precise. Option C also implies an agreement and is erroneous. Option D  is correct because refusing to yield means to refuse to give way, which is similar to 'putting one's foot down'. Option D is the correct answer.