The only crime mentioned in the U.S. Constitution is:

The mention of treason as the only crime in the U.S. Constitution underscores its historical significance and the serious nature of this offense. Article III, Section 3 of the Constitution specifically defines treason against the United States, stating that it consists only in levying war against them, or in adhering to their enemies, giving them aid and comfort. This inclusion reflects the founding fathers' concern about both internal and external threats to the new nation, considering treason to be a very grave offense that could undermine the stability and security of the government.

In contrast, the other options—murder and extortion—are serious crimes but are not explicitly referenced in the Constitution. Instead, they are governed by state laws and statutes. Thus, the specific mention of treason in the Constitution highlights its unique legal and historical importance in the context of American law.