Maintenance categories: changing the oil in an automobile is an example of which maintenance type?

Introduction / Context:
Maintenance strategies in operations and IT are often categorized as corrective (fix after failure), preventive (reduce likelihood of failure), and predictive (condition-based). For everyday equipment like cars, changing engine oil exemplifies how preventive actions are also placed on a calendar or usage schedule to ensure reliability and longevity.

Given Data / Assumptions:

• The task is routine oil replacement based on time or kilometers run.
• Objective: reduce wear, avoid breakdowns, maintain performance.
• Automotive maintenance schedules specify intervals (e.g., every 10,000 km or 12 months).

Concept / Approach:
Preventive maintenance is performed before failure to reduce risk. Scheduled maintenance is planned at fixed intervals or usage thresholds. Oil changes fit both definitions: they are preventive because they proactively protect the engine and scheduled because they typically occur at manufacturer-recommended intervals.

Step-by-Step Solution:

Verification / Alternative check:
Maintenance manuals and reliability engineering references classify routine consumable replacement (oil, filters) as preventive and frequently scheduled, confirming the combined categorization.

Why Other Options Are Wrong:

• Preventive or scheduled alone captures only part of the rationale.
• Neither/None: incorrect because oil changes are quintessential preventive and scheduled tasks.

Common Pitfalls:
Assuming preventive must be condition-based; in practice, time- or usage-based scheduling is a major form of preventive maintenance.

Final Answer:
both (a) and (b)