Answer:
C. The prosecutor .
Step-by-step explanation:
An antagonist is a person that works against the main character/ protagonist. He/ she represents the main enemy against which the protagonist is placed in opposition with.
In the given passage, the main protagonist is Holmes who is represented by Sanchez. And while she questions the move to plead not guilty for her client, she also knows that Holmes was a difficult man to work with, who insisted on maintaining his dignity even at the face of death. And in this scenario, the main antagonist is the prosecutor who, Sanchez admits, will use "so many shady tactics to make [Holmes] look guilty". The prosecutor is the one working against Holmes, trying to bring him down and triumph over him. Thus, the main antagonist is the prosecutor.