The Grand Jury
A. decide cases in the Supreme Court.
B. oversees judicial nominations.
C. reviews appeals in capital cases.
D. is a panel of judges who hear appeals.
E. investigate government officials for any misconduct.
Of these options, the only possible answer is Option D. Option D is not a great definition of a grand jury in most parts of the US, but it is much better than any of the other answers.
In most states that have grand juries (and at the federal level), a grand jury actually is a jury that decides whether there is enough evidence to charge a person with a crime and have them put on trial. Prosecutors present their cases to the grand juries and the grand juries decide whether to indict the defendant.
However, if you live in California, Option D may actually be a good answer. There is such a thing in California as a Civil Grand Jury. These grand juries do meet in every county to investigate the various government agencies. This fits well with Option D.
If you are in California, Option D is a good answer. Otherwise, as can be seen in the link below, it is not a very good answer, but it is the only answer that could possibly be right.