Answer:
d. The class gave her many ideas for the project, but she used only one.
Step-by-step explanation:
Active voice is when a subject is actively doing a verb. I completed the experiment.
Passive voice is when the subject is passively accepting a verb, or not actively doing something. The experiment was completed. (by whom? we're not super sure.)
Choice D is correct because it demonstrates a subject, the class, doing a specific action, giving. It keeps the same idea, which is that the girl used only one idea from the class.