The sentence in which the underlined infinitive phrase functions as a subject is the last one - to quickly move large groups of people is the purpose of public transportation.
<em>To quickly move </em>is the infinitive phrase, and it is a subject.
It's noun, most probably.
I literally have no idea what you're asking for ?
If you have to much food or if your young
You will need A. That is the one u need
