Which of the Following Statements Is FALSE

Which of the following statements is FALSE?

A) Nucleotides and amino acids can act as extracellular signal molecules.
B) Some signal molecules can bind directly to intracellular proteins that bind DNA and regulate gene transcription.
C) Some signal molecules are transmembrane proteins.
D) Dissolved gases such as nitric oxide (NO) can act as signal molecules, but because they cannot interact with proteins they must act by affecting membrane lipids.