Sentence 9, reproduced here, would best be rewritten as "____". (9) "Exploring the humanities encourages creative thought, the questioning of authority, think for yourself, question reality, and wonder about the purpose of life."

This answer is the only one that correctly creates parallel structure in the sentence. When you form a list, all verbs in that list must be in the same form instead of one being the -ing form and another being the infinitive (to __) form, etc.