My sister is tall.

  1. He
  2. She
  3. They
  4. We


A pronoun is a word that is used as a substitute of a noun. In a sentence, the form of pronouns vary according to to three kinds of persons (first, second and third), two kinds of number (singular and plural), and four kinds of gender(masculine, feminine, neuter and common).

The correct answer is: She

    The correct answer is "she".
    From the above-mentioned example, we can say that the speaker's sister is tall. Here, the subject is the speaker's sister and to represent it, we must use a third person singular number pronoun. Among the given options, the words "he" and "she" have a similar feature, but since Alice is a girl, a feminine gender pronoun must be used. So, the correct answer is "she".