To "exacerbate" a situation means to:

"Exacerbate" specifically refers to the act of making a situation more severe, intense, or harmful. When something is exacerbated, it becomes worse than it was previously. This term is frequently used in discussions about problems, issues, or conflicts, emphasizing a negative escalation rather than a resolution.

For example, in discussions related to health, if a disease is exacerbated, it means that the condition has deteriorated or complications have increased, rather than improved. This understanding of "exacerbate" aligns perfectly with the meaning presented in the correct choice.

The other options suggest positive actions or neutral outcomes, which do not reflect the essence of the term. The focus of "exacerbate" is solely on worsening a situation, making it distinct from efforts to improve, comprehend, or neutralize any adverse effects. Thus, it stands out clearly that to "exacerbate" means to intensify an existing problem.