Use the sentences to answer the question

4. Sullen

The word that would give the sentence a negative tone if it replaces the word quiet is "Sullen."

To answer this question, we can examine the context in the sentence where Aunt Lydia describes Mary as "quiet." Aunt Lydia expresses concern about Mary's future, implying that her quietness might have negative implications. To determine which word would give the sentence a negative tone if it replaces "quiet," we can evaluate the connotations of each option.

1. "Disciplined" does not necessarily have a negative connotation. It implies that someone follows rules and has self-control.
2. "Reserved" also does not inherently convey a negative tone. It suggests that someone is introverted or keeps their emotions to themselves.
3. "Calm" is generally associated with a positive connotation. It means being peaceful and composed.
4. "Sullen" is the word that would give the sentence a negative tone. It implies a gloomy, moody, or sulky temperament.

Therefore, the word "sullen" (option 4) would give the sentence a negative tone if it replaces "quiet."