Spoilt for multichoice

If the procedures in the example below are followed, students soon cease to guess. With five possible answers, the odds of getting the right answer are not worth the risk of guessing. Rubric: Select and tick one answer. A mark of one will be given for the correct answer; a mark of minus one for a wrong answer and a mark of zero for "Don't Know".

Question: What is the administrative capital of Australia?

( ) Adelaide ( ) Brisbane ( ) Canberra ( ) Melbourne ( ) Sydney ( ) Don't Know B. Richards Department of computation, UMIST.