For a shoe brake, the equivalent coefficient of friction is equal to (where = Actual coefficient of friction, and = Semi-block angle)

• A. <img src="/_files/images/mechanical-engineering/machine-design/594-455-1.png">
• B. <img src="/_files/images/mechanical-engineering/machine-design/594-455-2.png">
• C. <img src="/_files/images/mechanical-engineering/machine-design/594-455-3.png">
• D. <img src="/_files/images/mechanical-engineering/machine-design/594-455-4.png">