The answer to your question is c.invented because it's a past participle.
Answer: A.) At this point in his life he was familiar with the basic science of electricity.
Explanation: This answer makes the most sense out of all of them and the sentence gives reason enough to believe said character has some knowledge on the laws of electricity. Taking this based off the words "I was not unacquainted with the more obvious laws of electricity." Meaning said character had some prior knowledge, so we can assume he is familiar with the basic science of electricity.
My peeennnooooorrrrrrrrrrrr
Answer: I think it would be dictatorship
Explanation: but if it’s not then you can try
Aristocracy or monarchy
Metaphor I tried hope you find the answer
