Which Statement Regarding Heterotrimeric G Proteins in a Resting State $\beta$

Which statement regarding heterotrimeric G proteins in a resting state is true?

A) GDP is bound to the $\beta$ subunit in a complex with both the $\alpha$ and $\gamma$ subunits.
B) GDP is bound to the $\alpha$ subunit in a complex with both the $\beta$ and $\gamma$ subunits.
C) GTP is bound to the $\alpha$ subunit in a complex with both the $\beta$ and $\gamma$ subunits.
D) The proteins are in a complex with G protein-coupled receptors.