Final answer:
The correct statement about planned maintenance systems is that they involve scheduled and preventive maintenance activities planned in advance to prolong equipment life and prevent failures.
Step-by-step explanation:
The statement that pertains to the planned maintenance system is: c) It involves scheduled and preventive maintenance. A planned maintenance system is one in which activities are planned and scheduled in advance, involving routine checks, servicing, and upkeep of equipment, machinery, or systems to prevent breakdowns and ensure optimal functioning. This approach contrasts with reactive maintenance, which occurs in response to a problem or failure.