All categories are options, none of which has been, since 2004, s and b are very useful if you create that, but if not, well, "was all" candidate will not choose at all if they are confident that there is at least one option could not be.
Type Options All of the above, none of the above, data, and B is the creation of well-considered helpful, but if you create a bad example, "all of the above" the test is not an option at all if they are convinced that there is a choice of at least 1 or not. cheap
Option types, certain of, no any right, cross, and of being, if build well considered beneficial, but if create bad, such as "all are correct." the examinees will not choose if he sure has the option, at least 1 not