In South Dakota v. Department of Interior, the delegation of power to the Secretary of

the Interior to acquire land in trust for the Lower Brule Tribe of Sioux Indians was
declared unconstitutional because:

a. the Lower Brule Tribe of Sioux Indians was not recognized as a legitimate tribe eligible for benefits in the authorizing Act
b. the enabling statute did not articulate the underlying public use that justified the acquisition and the secretary's power to purchase land was not properly defined
c. Congress may delegate authority to purchase open federal land but not private land such as land within established city limits (the City of Oacoma)
d. the statute provided an unfair advantage to Indians, putting other Constitutionally
protected groups at a disadvantage
e. all of the above

b