Final answer:
The online studying device shown in class is Flashcard DB, which facilitates the creation, use, and sharing of flashcards for studying.
Step-by-step explanation:
The online studying device that was shown in class is c. Flashcard DB. This application allows students to create, use, and share flashcards for various subjects, making it an effective tool for studying. Applications like Flashcard DB are valuable resources for students, as they provide interactive and accessible ways to review and memorize information. When your professor suggests utilizing web-based sample quizzes, animations, or study guides, it's beneficial to embrace these modern studying strategies to enhance your learning process.