If a FRET Experiment Was Carried Out with Blue Fluorescent $\alpha$

Multiple Choice

If a FRET experiment was carried out with blue fluorescent protein attached to the $\alpha$ subunit of a stimulatory G-protein and a green fluorescent protein attached to the $\beta$ subunit, the presence of a strong FRET signal would be associated with:

A) interaction of a G protein-coupled receptor with an antagonist.
B) hydrolysis of GTP in the $\alpha$ subunit.
C) increased concentrations of cAMP.
D) both interaction of a G protein-coupled receptor with an antagonist and hydrolysis of GTP in the $\alpha$ subunit.
E) both hydrolysis of GTP in the $\alpha$ subunit and increased concentrations of cAMP.