How Might RNAi Be Used to Treat Diseases in Humans

How might RNAi be used to treat diseases in humans?

A) siRNAs could be generated that would silence elevated levels of a harmful gene.
B) An RNAi library could be generated to assay harmful gene expression levels.
C) RNAi probes could bind to good genes and thus increase their expression.
D) RNAi could be used to amplify large amounts of therapeutic proteins.
E) RNAi cannot be used in humans, as it is a process found only in plants.