A.I. Explanation:

Option 1: "They must study the handouts and actively participate in the class."

Explanation: The text emphasizes that active class participation is the most important factor for achieving a good grade, and it also mentions that studying the handouts will help make the tests easier. This aligns perfectly with the main idea of the text, which is about the importance of both studying and participation in class.

Option 2: "They must get a good score on the written test."

Explanation: While doing well on the written test can contribute to a good grade, the text states that the written and oral tests are only a small portion of the final grade. Therefore, this option is misleading as it implies that the written test is the primary focus, which contradicts the overall message of the text.

Option 3: "They have to study more for the oral test."

Explanation: The text does not emphasize the need to study more specifically for the oral test. Instead, it highlights the importance of studying the handouts and participating in class as the key factors for good grades. This option is incorrect because it narrows the focus to just the oral test, which is not supported by the text.

Option 4: "Only class participation is important."

Explanation: This option incorrectly suggests that class participation is the sole factor for good grades. The text clearly states that both studying the handouts and active participation are important, making this option incomplete and misleading.