Each question is designed to assess how well you understand a keyword or concept.
We are leveraging a multiple-select (multi-select) question with only one answer to assess the learner's ability to discriminate between multiple options. When there is a single correct answer to a question, we should use a single select item. When multiple measures could be correct, even if they are not included in the set of options, then multi-select is appropriate. Another reason we use multi-select with only one answer is to avoid giving a clue to the learner that every time they see a multi-select question, there are at least two correct options.