Step 1: Define Benevolent.
"Benevolent" comes from Latin "bene" (well) + "volens" (wishing); it means well-meaning, kind, generous, and charitable toward others - someone who actively wishes and does good for people around them.
Step 2: Identify synonyms among the options.
"Kind," "Generous," and "Helpful" are all synonyms of Benevolent - they express the same warm, giving attitude; none of these can be the antonym.
Step 3: Identify the antonym.
"Cruel" means deliberately causing pain or suffering to others - the direct opposite of a well-wishing, caring attitude; Cruel is the clear antonym of Benevolent.
\[ \boxed{\text{Cruel}} \]