String Response problems allow the student to submit a string of characters for the answer. Examples of String Response questions are vocabulary tests, short answers and chemical formulas.
Note that it is easy to abuse String Response problems. For instance, consider the question "Who wrote 'Huckleberry Finn'?" If you tell the system the answer is "Mark Twain", and a student answers "Twain", the system will mark it wrong. If they answer "Samuel Clemens", then the student will definitely get it wrong. There is some room for flexibility in the string processing, but it can be difficult to get it all correct. Before you use a String Response problem, be sure you can easily characterize correct answers.