C
When a person is charged with a federal crime, the first level of the judicial system they will most likely encounter is a U.S. district court. The U.S. Attorney, who represents the United States in most court proceedings, including all criminal prosecutions, initiates a criminal case in coordination with a law enforcement agency. At the beginning of a federal criminal case, the principal actors are the U.S. Attorney (the prosecutor) and the grand jury. The grand jury reviews evidence presented by the U.S. Attorney and decides whether it is sufficient to require a defendant to stand trial. If the grand jury decides that there is enough evidence, the defendant will be indicted and arraigned in a U.S. district court
Therefore, option C is correct.