On the navbar, click the Activities menu, then select Quizzes.
On the Manage Quizzes page, from the context menu of the quiz, click Grade.
Click on the Questions tab.
Select Update All Attempts.
Click the quiz question that you want to grade.
In the Grade Type area, choose to Give to attempts with answer____ ____ points. Select the answer you want to add and enter the points the students will earn for the answer.