Which property distinguishes peptide/protein hormones like insulin from steroid hormones in terms of receptor location and signaling mechanism?

• A. Protein hormones are primarily structural proteins repurposed for signaling, while steroids are made of amino acids similar to proteins and use identical receptors
• B. Protein hormones always cross the cell membrane and bind directly to DNA to change gene expression within seconds, whereas steroids act only on surface enzymes
• C. Protein hormones are typically water-soluble and bind to membrane receptors to trigger intracellular signaling cascades, whereas steroid hormones are lipid-soluble and often bind intracellular receptors that modify gene transcription
• D. Protein hormones are stored as triglycerides in adipose tissue and released on demand while steroid hormones circulate bound to albumin and act by immediate enzyme inhibition

Answer: (C)