What was the relationship of Abigail to Nabal the Carmelite?

Abigail was Nabal's wife, making her his widow after Nabal dies. In the biblical narrative found in 1 Samuel 25, Abigail is described as a wise and discerning woman who intervenes when David seeks vengeance against Nabal for his refusal to provide provisions to David and his men. After Nabal's death, Abigail becomes David's wife, which further solidifies her status as a widow before her marriage to David. This context supports the answer that Abigail is Nabal's widow.

The other relationships mentioned in the various options do not accurately reflect Abigail's role in relation to Nabal, as she was not his daughter, sister, or mother.