The Constitutional right that forbids Congress from sending a person to prison is the writ of habeas corpus.
The correct answer is the "writ of habeas corpus." The writ of habeas corpus is a constitutional right that forbids Congress from sending a person to prison without a fair trial or due process. It ensures that individuals have the right to challenge their detention by petitioning a court for a review of the legality of their imprisonment. This protection is critical to prevent unjust detentions and is an essential safeguard for individual liberty.