The underlined pronoun in the sentence is "we" and it is used as a subject. The correct answer is option B. The sentence given above has a compound subject, Grandma and we. We used the pronoun "we" instead of "us" because "we" is a subjective pronoun. Subjective pronouns are pronouns that are used as subjects in the sentence. Other subject pronouns include I, you, he, she, it and they.