Why can't I release scores?
If you made an assignment with the Assessment Option "Do not assign assessment questions," then there are no total scores for your assignment to release. Therefore, the Release Scores option will not be visible for the assignment.
If you enabled Guided Reading Mode for the assignment, students will see feedback on their performance as they answer the question. If you leave feedback on students' annotations, they will not be notified, so be sure to instruct them to regularly check their assignments for feedback on their annotations.