Respuesta :
The correct answer is C. Sunlight is beneficial to most plants.
The root bene- means good or well, and the word beneficial, which is derived from that root, means something favorable, useful, helpful, good for something else.
In sentence A, beneath (meaning below) is not derived from bene-. In sentence B, benediction is derived from bene-, but it means fortunate wishes, and doesn't fit the context. In sentence D, benevolent is also derived from bene-, but it means kind, good-hearted, which is also incorrect for this context.