While Having a Discussion, Technician a Says That a Solenoid

Multiple Choice

While having a discussion, Technician A says that a solenoid has contact points, whereas a relay uses a movable iron piston attached to a contact disc. Technician B says that a relay has contact points, whereas a solenoid uses a steel piston moved against a contact disc by magnetism. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B