How Is G Protein-Mediated Signaling Terminated

How is G protein-mediated signaling terminated?

A) Desensitization of the G protein-coupled receptor terminates the signaling previously initiated by active G proteins.
B) Hydrolysis of GDP to GTP by the endogenous GTPase activity of the α-subunit leads to reassociation of the αβγ-complex, terminating the response.
C) Exchange of GDP for GTP by the endogenous GTPase activity of the α-subunit leads to reassociation of the αβγ-complex, terminating the response.
D) Exchange of GTP for GDP by the endogenous GTPase activity of the α-subunit leads to reassociation of the αβγ-complex, terminating the response.
E) Hydrolysis of GTP to GDP by the endogenous GTPase activity of the α-subunit leads to reassociation of the αβγ-complex, terminating the response.