In a flat collar pivot bearing, the moment due to friction is proportional to

• A. <img src="/_files/images/mechanical-engineering/theory-of-machines/487-184-1.png">
• B. <img src="/_files/images/mechanical-engineering/theory-of-machines/487-184-2.png">
• C. <img src="/_files/images/mechanical-engineering/theory-of-machines/487-184-3.png">
• D. <img src="/_files/images/mechanical-engineering/theory-of-machines/487-184-4.png">