The suggested answer is C.
When handling a ransomware infection, the technician's first priority should be to prevent the malware from spreading or causing further damage. Quarantining the system is the most appropriate initial step. This will isolate the infected machine from the network and other devices, helping to contain the threat and limit its potential impact. Once the system is quarantined, further steps such as scanning and removing the malware, disabling System Restore, and scheduling automated malware scans can be taken.