To correctly answer a Parallel question, we can follow three steps: (1) understand the argument in the stimulus, (2) identify the abstracted structure of that argument, and (3) match that structure to the correct answer choice. These steps aren't always easy, but if we can successfully complete each one, we'll always get to the right answer.

(1) understand the argument. An anthropologist concludes that the Zi is the only known culture from a particular area that could have made inscriptions at a particular site in that area. Why? Well, there are three known cultures from that area: the Xa, the Ye, and the Zi. Whichever culture made the inscriptions must have used fire to make iron tools. And neither the Xa nor the Ye could have done so—the Xa couldn't use fire to make tools, and the Ye didn't have any iron.

(2) identify the argument's structure. The anthropologist's argument proceeds by eliminating options for who might have made the inscriptions until only one option remains. Of the set of options defined by the anthropologist (cultures known to be from the area), the anthropologist finds reasons to eliminate two out of three options and then concludes that the remaining option is the only possible option from the defined set.

(3) match with an answer choice. It's often time-consuming to assess each answer choice for Parallel questions, but to help with that we can do a preliminary elimination round by checking the answer choices' conclusions. Any answer choice with a non-matching conclusion (i.e. a conclusion which doesn't arrive at a final remaining option) can be eliminated without further consideration. For the remaining answer choices, we can do a deeper step-by-step analysis to check which one matches every part of the stimulus. If we get stuck between two answer choices, we can also compare the answer choices to find the difference, and from there determine which one matches the stimulus.