Why does Pony have a problem with Johnny's idea to disguise themselves?
The long hair of the Greasers is a symbolic representation of who they are and what they stand for. Ponyboy does not want to cut his hair because it is all he has left of the life that they have left. He believes that it is the hair that makes him who he is, a Greaser.

Explanation:

Pony has a problem with Johnny's disguise idea themselve in the outsiders because he believed his hair was tuff and doesn't want to cut his hair that took so long to grow and that it symbolizes that he is a greaser which was his pride and by losing his hair he would be losing a part of himself which stand as a trademark of been a Greaser.

the correct answer is 4) infinitive phrase with a direct object

the explanation is that the infinitive phrase, "to with the younger children", functions as the object. it means the thing that the subject does.

1) no infinitive is incorrect because there is an infinitive verb in the sentence.

2) an infinitive only is incorrect because it is not in isollation. it is part of an infinitive phrase.

3) infinitive phrase with a subject is incorrect because in this example the infinitive phrase does not function as the subject doing the action of the sentence.