Final answer:
The second step in the scientific method is generating a hypothesis, which is a tentative and testable explanation for observed phenomena.
Step-by-step explanation:
The second step in the scientific method is: c. generating a hypothesis. After observing and asking questions about a phenomenon, scientists conduct some initial research. Based on this research and their observations, they form a hypothesis, which is a tentative explanation designed to address the observation(s). This hypothesis should be testable and sets the stage for further experimentation to either support or refute the proposed explanation. Therefore, the correct answer to the student's question is generating a hypothesis.