A technical lead who was working on a major project has left the organization. The project manager reports suspicious system activities on one of the servers that is accessible to the whole team. What would be of GREATEST concern if discovered during a forensic investigation? 
A、Audit logs are not enabled for the system 
B、A logon ID for the technical lead still exists 
C、Spyware is installed on the system 
D、A Trojan is installed on the system