When Different Transmitters or Hormones Act Through Different G Protein-Coupled

When different transmitters or hormones act through different G protein-coupled metabotropic receptors,

A) each receptor is always coupled to a different type of G protein.
B) multiple receptors can be coupled to the same type of G protein.
C) the G protein that is coupled to the receptor is determined by the transmitter or hormone that is the ligand for that receptor.
D) the second messenger cascade that is coupled to the receptor is determined by the transmitter or hormone that is the ligand for that receptor.
E) the second messenger cascade that is coupled to the receptor is always determined by the specific G protein type that is coupled to that receptor.