What should a critical thinker do when the meaning of a word is not clear?

Select the correct answer from each drop-down menu. read the following excerpt from the novel "oliver twist" by charles dickens. although oliver had been brought up by philosophers, he was not theoretically acquainted with the beautiful axiom that self-preservation is the first law of nature. if he had been, perhaps he would have been prepared for this. not being prepared, however, it alarmed him the more; so away he went