With regard to the physics of power systems used operate robots, which statement or statements are most correct?
(a) hydraulics involves the compression of liquids
(b) hydraulics involves the compression of air
(c) pneumatics involve the compression of air
(d) chemical batteries produce AC power
The question was asked during an interview for a job.
Enquiry is from Robotics topic in portion Communicating, Perceiving and Acting of Artificial Intelligence