Which of the following best describes corrective maintenance?

Corrective maintenance is defined as maintenance that is carried out after a malfunction or failure has occurred in order to restore the equipment or system to a fully operational state. This type of maintenance is reactive, meaning it is initiated in response to an issue rather than being scheduled in advance. It contrasts with preventive maintenance, which aims to prevent failures before they happen through regular checks and tasks.

In this context, the other options represent different concepts within the maintenance spectrum. Scheduled tasks refer to maintenance that is planned and performed on a regular basis, regardless of whether an issue arises. Preventive maintenance focuses on actions taken to avoid future malfunctions rather than addressing existing problems. Adjustments made during routine checks relate more to inspections and minor tweaks rather than the broader scope of fixing failures. Thus, the definition of corrective maintenance aligns specifically with addressing failures after they have happened, making it the best descriptor among the choices provided.