What is the purpose of a "grand jury"?

A grand jury serves a critical role in the legal system, primarily functioning to decide whether there is sufficient evidence to formally charge someone with a crime, known as an indictment. This body of citizens evaluates evidence presented by the prosecutor to determine if there is probable cause to believe that a crime has occurred and that the accused individual should be formally charged.

During this process, the grand jury does not make determinations of guilt or innocence; such decisions are reserved for a trial jury after an indictment has occurred. Additionally, the grand jury does not impose sentences as that responsibility lies with the judge in a trial following a conviction. Hearing appeals from lower courts is another judicial function that does not fall under the grand jury's authority.

In summary, the grand jury's purpose is specifically to assess whether there is enough evidence to proceed with criminal charges, making option B the correct choice.