Which of these phrases is the infinitive phrase in the sentence? the firefighters' intention, to save the house, intensified quickly

An infinitive phrase is a set of words comprising of the word 'to' plus a verb in its simplest form working as a noun, adjective, or an adverb. So in the question, the answer is to save the house, that is the infinitive phrase.

As for this question together with the options presented with it, the most probable answer and the most likely one to be the correct answer is the third option which is C. group discussions.

Though critical listening can also be utilized in the other situations presented as options, critical listening would be very useful during group discussions. During conversation with friends and family, it isn't advisable since it might ruin the bond build between parties and might instigate something worse. During a play, yes, you can, but not all the time. In persuasive speeches, it is more on the details that are being thrown.