An advantage of using fluorescent protein technology to track protein movements in cells and tissues is that

A) intracellular GFP-protein fusions can be detected by fluorescence microscopy in vivo.
B) a mobile protein can be tracked as it moves through organs or tissues.
C) a fusion with a mutant protein might reveal incorrect localization or movement.
D) it can identify the gene encoding prey protein.
E) it can be used to detect protein-protein interactions.