The velocity ratio of the differential wheel and axle is

• A. <img src="/_files/images/civil-engineering/applied-mechanics/115-5.219-1.png">
• B. <img src="/_files/images/civil-engineering/applied-mechanics/115-5.219-2.png">
• C. <img src="/_files/images/civil-engineering/applied-mechanics/115-5.219-3.png">
• D. <img src="/_files/images/civil-engineering/applied-mechanics/115-5.219-4.png">