It was a kind of computer with which I was not familiar.
So, the correct option is:
The group of words, "with which" is a fusion of a preposition and a pronoun. It can be used in a sentence to add further details about the noun.
The noun in the sentence given is Computer. The phrase adds more emphasis to this noun.
Learn more about phrases here:
https://brainly.com/question/7744384
