The relative pronoun is ''Which'' because relative pronouns connect to a clause or phrase to a noun or pronoun.
The answers of the given sentences above are the following:
1. The pronoun "he" in this sentence is used as a SUBJECT.
2. The pronoun "she" in this sentence is used as a PREDICATE NOMINATIVE.
3. The pronoun "he" in this sentence is used as a PREDICATE NOMINATIVE.
20 mph in general but there have been know to be expectations <span />
They are triangles and the base is a square