ACO – it means that your result is deferred pending further investigation.
Your report / presentation slide and/or SLS most likely showed too many similarities with another student’s work [past or present] and indicated some collusion / copying / plagiarism. Alternatively its content or style caused the marker to question whether it had been written by you [or the mentor / an academic paper writing service].
They will contact you in time to discuss and after then they will let you know the outcome and result.