Every night before studying, Sonya has a banana. One day, she has no bananas left, so she eats a cookie. Sonya notices that she has a hard time studying. The next night, Sonya has a banana again and does not have a hard time studying. What new question would be best for Sonya to ask based on her discovery? A. Do all students study at night? B. How often do I need to study to get good grades? C. Do all types of fruit help me study? D. What are my classmates' favorite foods? (its C)