Multiple choice questions are auto-scored. When scoring an assignment, the circle next to the page headers indicates the score for that page.
For example, in the assignment below, Page 5 has three multiple choice questions. The student answered one question correctly and two were marked as incorrect. The score for the assignment page is reflected in the circle to the right: 1/3.
When looking at the questions individually, we can see which questions the student answered correctly or incorrectly based on the color highlighted in the multiple choice options.
Green: The student answered B for this question. B is the correct answer so it is highlighted green.
Red: The student answered B for this question. B is not the correct answer so it is highlighted in red. The correct answer A is highlighted in yellow.
Yellow: The color yellow reflects the correct answer when the student answered the question incorrectly (as shown above) or did not answer the question at all (as shown below).
Notice that the 0, 0.5, and 1 buttons are not selected for these questions even though they are auto-scored (as represented by the highlighted colors and the circle with the page score).
These are available for you to override the score if needed but are not needed to score a multiple choice question.