You're right, there's no stimulus here. However, this is a drilling question, and the goal of this question is to help you better gain familiarity with the different types of question stems that appear on the LSAT. Therefore, the only thing that matters is that the question stem appears, as what you're trying to do here is pick the answer that matches the question stem.
The question stem asks us which of the following would be most important to answer in evaluating the conclusion. We know from this that we're evaluating the argument, so this question type is an argument evaluation, which is answer E.
Hope this helps. Let us know if you have any other questions!
