a) When was the first actual robot invented and used?
Willard Pollard and Harold Roselund invented a mechanical arm with joints for an automated spray-painting machine, in 1938.

b) In 1942, science fiction writer Isaac Asimov created a set of three imaginary Laws of Robotics. What was the name of the book Asimov wrote in 1942 in which he described the Laws of Robotics?
The book that Asimov wrote in 1942 describing the Laws of Robotics was called "Runaround".

c) What is the so-called "Zeroth" Law of Robotics? Why is it called the Zeroth Law?
fusionanomaly.com repeats the Zeroth Law, which states that "A robot may not injure a humanity or, through inaction, allow humanity to come to harm". According to Google definitions, Zeroth means "the initial item of a sequence, if that sequence is numbered beginning from zero rather than one". According to Future Positive, it is called the Zeroth Law because although it was created fourth chronologically, it was logically the First Law.

d) Propose one situation where it would be OK for a robot to harm (or even kill) a human. Explain why it would be OK in this circumstance.
A robot that does eye surgery, although it will eventually help the patient, is harming them in the process. This is OK because the harm that has been done will eventually be outweighed by the positives of the surgery (ie better eye sight)