Final answer:
Mrs. Mallard initially grieves over her husband's death but then feels liberated, anticipating a future of independence and freedom. The 'heart trouble' is both a real ailment and a symbol of her constrained existence. The joy of her liberation is so intense that when her husband returns alive, the shock causes her death.
Step-by-step explanation:
The news of her husband's death has a profound impact on Mrs. Mallard. Reflecting the correct answer to the student's question, she is at first overcome with grief, but this soon gives way to a feeling of freedom and independence. After the initial shock and grief, Mrs. Mallard retreats into solitude where she recognizes the death of her husband, Brently Mallard, as an opportunity for self-assertion. She experiences a sense of relief and foresees a future where she can live for herself, free from the oppression of her marriage.
The significance of Mrs. Mallard's 'heart trouble' is both literal and symbolic, indicating her physical frailty as well as her psychological confinement within her marriage. In a moment of clarity, she welcomes her newfound freedom with hope and elation. However, this joy is short-lived, as the unexpected return of her supposedly deceased husband results in her sudden death, which the doctors attribute to 'the joy that kills'.