What is the correct form to fill in: After the first few lessons, she _____ the whole class talking?

The correct choice in this context is "made." When considering the sentence, "After the first few lessons, she _____ the whole class talking," the word "made" effectively conveys that she caused or compelled the whole class to engage in conversation. This aligns with the common expression "made someone do something," emphasizing her role in initiating the discussion among the students.

Using "made" in this context indicates an active role in creating an atmosphere where talking was possible, possibly through her teaching style or the activities she implemented. This fits naturally into the narrative of a classroom setting where a teacher influences the dynamics of student interaction.

The other choices do not align with the meaning intended in the sentence. For instance, "gets" could suggest an ongoing action but doesn't provide the sense of causation. "Had" implies a completed action but lacks the immediacy or impact of instigating the class's talking. "Involved" suggests participation but does not carry the same force of initiation as "made." Thus, "made" is the most appropriate choice for portraying her influence on the class's engagement.