Final answer:
In "Desiree's Baby," the theme 'Betrayal leads to despair' is the best fit, describing the consequences of Armand Aubigny's rejection of Desiree and their child based on assumed racial heritage.
Step-by-step explanation:
In "Desiree's Baby," the universal theme that best fits the passage is B) Betrayal leads to despair. The story revolves around Desiree, a young woman who marries Armand Aubigny and later gives birth to a child with African ancestry.
When Armand assumes that Desiree is of mixed descent, he rejects her and their baby, leading Desiree into a profound state of despair. This act of betrayal by Armand, premised on racial prejudice and false assumptions, highlights the theme of how betrayal can lead to deep despair and sorrow for those affected.