Answer:
D.
Step-by-step explanation:
Based on the information provided surrounding this scenario, it can be said that the most likely next course of action would be to create an alternate user ID to maintain persistent access. This would allow the attacker to have continuous access into the network in the case that the system administrators detect that the operator's user ID and password have been compromised. Thus also giving the attacker ample time to infiltrate and find vulnerabilities in the network through an alternate hidden user ID.