Spindle
Tie rod
Differential
None of these
T-Joints
Ball Joints
Straight joints
Self locking braking system
Skid locking braking system
Anti locking braking system
Lever
Screw
Wedge
Pulley
Valve recess
Crescent hole
Valve cup
The crescent shaped cavity on the piston head top surface is called as valve recess.