In your molecular biology class you make two different cDNAs. The first cDNA expresses a green fluorescence protein (GFP) fused to the retinoid hormone receptor. The second cDNA expresses a red fluorescent protein (RFP) fused to the glucocorticoid receptor. You express both cDNA's in the same mammalian cell in a dish and you examine their appearance using a microscope equipped with fluorescence optics. You then add retinoid and glucocorticoid ligands to the dish and wait for 30 min before re-examining the cells. Which colors would be seen in the nucleus and the cytosol before and after addition of the ligands ?

(A) Red and green fluorescence in nucleus before and after addition of ligands.
(B) Red fluorescence in cytoplasm and green fluorescence in nucleus before addition of ligands; red and green fluorescence in nucleus after addition of ligands.
(C) Green fluorescence in cytoplasm and red fluorescence in nucleus before addition of ligands; red and green fluorescence in nucleus after addition of ligands.
(D) Red and green fluorescence in cytoplasm before and after addition of ligands.
(E) Red and green fluorescence in cytoplasm, but not nucleus before addition of ligands; red and green fluorescence in nucleus after addition of ligands.