Answer:

The correct answer is option 'A' - Relative pronoun.

Explanation:

Relative pronouns are used to connect a dependent clause to its antecedent (the noun that the clause is describing or referring to). In this sentence, the word "who" is a relative pronoun.

Relative pronouns introduce relative clauses, which provide additional information about a noun in the main clause. They can refer to people, animals, things, or ideas. In this sentence, the relative pronoun "who" is referring to the noun "cousin" and provides additional information about her.

Examples of relative pronouns:
- who: used for people
- which: used for animals and things
- that: used for people, animals, and things

Usage of relative pronouns:
- The relative pronoun "who" is used to refer to people. In this sentence, "who" is used to refer to the person "Rita". It connects the dependent clause "who lives in New York" to the noun "cousin" in the main clause.
- Relative pronouns are essential in providing more information about the noun and connecting the dependent clause to the antecedent. They help to clarify the subject or object of the sentence.

Other pronoun types:
- Personal pronouns are used to refer to specific people or things. Examples include "I", "you", "he", "she", "it", "we", and "they". These pronouns replace nouns in a sentence.
- Indefinite pronouns are used to refer to non-specific people or things. Examples include "someone", "anyone", "everyone", "something", and "nothing". They refer to an unspecified person or thing.
- Reflexive pronouns are used when the subject and object of a sentence are the same. Examples include "myself", "yourself", "himself", "herself", "itself", "ourselves", "yourselves", and "themselves". They reflect back to the subject.

In conclusion, the word "who" in the given sentence is a relative pronoun because it connects the dependent clause to the noun and provides additional information about the person "Rita".