Escherichia coli etec ehec

What molecule is increased by the heat-labile toxin produced by enterotoxigenic Escherichia coli?

1: Adenosine triphosphate (ATP)
2: Cyclic adenosine monophosphate (cAMP)
3: Guanosine triphosphate (GTP)
4: Cyclic guanosine monophosphate (cGMP)