What type of pronoun is used to show the connection between the antecedent and the subordinate clause of a sentence demonstrative indefinite relative interrogative?

A relative pronoun introduces a subordinate clause, called a relative clause. A relative clause 'relates' information about it's antecedent.

The relative pronouns are: who, whom, whose, which, that.

Examples:

The actor who played Hamlet was Excellent.

The man whose car I hit was very nice about it.

The shoes that I bought were very expensive.

The customer for whom I made that cake will pick it up at four.

I found the book which is out of print at the book fair.