Which Is the Best Method to Demonstrate the Function of a Putative

Which is the best method to demonstrate the function of a putative enhancer?

A) Clone a region of DNA with the putative enhancer into a reporter construct, introduce the construct into eukaryotic cells, and measure expression of the reporter protein.
B) Compare DNA sequences from two or more species and identify conserved regions located outside of coding regions.
C) Introduce two separate pieces of DNA into a eukaryotic cell; one is a fragment of DNA with the putative enhancer and the other is a plasmid that contains a reporter gene.
D) Clone the putative enhancer into a reporter construct and measure the level of reporter gene expression in a prokaryotic cell.
E) Crosslink genomic DNA and associated proteins, fragment the DNA, use an antibody to isolate DNA sequences bound to a particular transcription factor, and sequence the DNA.