Final answer:
For troubleshooting hardware and drivers, HKEY_LOCAL_MACHINE is the registry hive most likely to be edited due to its storage of hardware and software configuration information.
Step-by-step explanation:
When troubleshooting hardware and drivers, the most likely registry hive you will edit is c) HKEY_LOCAL_MACHINE. This hive contains information about the hardware and software configuration of the system. For instance, if a hardware device is not functioning properly, information within the Device Manager and concerning driver installations can be found and edited within this hive. It is crucial to be very careful when editing the registry as improper changes can lead to system instability or even failure to boot.