This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following most accurately describes the transmembrane  signaling  process  involved  in  the steroid hormone action? 
Select and explain. 
A. Action on a membrane spanning tyrosine kinase, B. Action of a G protein, which activates or inhibits adenylyl cyclase, C. Diffusion across the membrane  and binding to an  intracellular receptor, D. Opening of transmembrane ion channels
C: Diffusion across the membrane  and binding to an  intracellular receptor
Answer: C: Diffusion across the membrane  and binding to an  intracellular receptor 
Explanation: Steroid hormones are lipid soluble and act on cytoplasmic receptors after crossing the plasma membrane.