A newly promoted chief audit executive (CAE) is faced with a backlog of assurance engagement reports to review for approval. In an attempt to attach a priority for this review, the CAE scans the opinion statement on each report. According to IIA guidance, which of the following opinions would receive the lowest review priority?

1. Graded positive opinion.

2. Negative assurance opinion.

3. Limited assurance opinion.

4. Third-party opinion.