Benevolent describes someone or something characterized by kindness, generosity, or a desire to do good, often in a selfless way (e.g., a benevolent leader). The opposite would describe someone who causes harm or acts with malice.
Option (C) cruel, meaning deliberately causing pain or suffering, is the direct antonym. Options (A) generous and (B) kind are synonyms of benevolent, as they share similar positive connotations.
Option (D) helpful is also a positive trait related to benevolence, not its opposite. Testing in context (e.g., A benevolent act helps others; a cruel act harms them) confirms (C) as the correct antonym.