In a ventilated disc brake,

A)
caliper is covered with cooling fins
B)
disc contains many small holes for optimum cooling performance
C)
a duct directs air towards the caliper for cooling while the vehicle is moving
D)
disc contains radial vanes between its rubbing surfaces for optimum cooling performance

Correct Answer : Option (D) :   disc contains radial vanes between its rubbing surfaces for optimum cooling performance