Students can "eliminate" an answer choice they think is wrong when taking a content assessment.
If you hover the mouse over an answer choice, an "X" will appear to the right of it. Clicking this "X" will eliminate or grey out the answer choice.
If an answer choice does get greyed out, it cannot be chosen as the correct answer. All greyed out answers can be restored by clicking the arrow that appears next to it or by clicking the answer bubble. This will make the answer open for selection again.