Final answer:
OSHA's lockout/tagout regulations primarily aim to control hazardous energy during maintenance, ensuring the safety of workers by preventing accidental machine start-ups.
Step-by-step explanation:
The primary purpose of OSHA's lockout/tagout regulations is C) Controlling hazardous energy during maintenance. These regulations are meant to ensure that machines are properly shut off and cannot be started up again prior to the completion of maintenance or repair work. This practice protects workers from the release of hazardous energy that could cause injury or death. OSHA standards require employers to implement a comprehensive energy control program that includes training, energy control procedures, and employee protection measures.