QUESTION $30$Regarding the $2016$ U$.$S$.$ presidential election, no evidence of cyberattacks resulting in altered voting tallies has been found. At that time, such tampering by foreign cyber$-$intelligence hackers would have been difficult to execute because:O a the voting machines themselves were not connected to the InternetO b$.$ the hackers had no way to profit from even successful attacks on voting machinesO c$.$ white$-$hat hackers employed by local election authorities could foil the cyberattacksO d$.$ U$.$S$.$ intelligence agencies pre$-$emptively attacked the hackers' networks with StunetOe. the voting machines themselves had military$-$grade firewalls to repel cyberattacks