Green Fluorescent Protein (GFP)can Be Used to Fluorescently Label a Specific

Green fluorescent protein (GFP) can be used to fluorescently label a specific protein in cells by genetically engineering cells to synthesize the target protein fused to GFP. What is the advantage of using GFP fusions to visualize specific proteins, instead of staining cells with fluorescently labeled probes that bind to the target protein?

A) GFP fusions enable one to track changes in the location of the protein in living cells; staining usually requires preserved cells.
B) GFP fusions enable higher resolution than staining with fluorescent probes.
C) GFP permits the position of the protein in the cell more precisely than fluorescent probes.
D) GFP permits visualization of protein-protein interactions; fluorescent probes do not.
E) GFP fusions are not subject to artifacts; fluorescent probes may introduce background artifacts.