What is the correct signal transduction pathway for a typical mammalian olfactory receptor (Or) in the main olfactory epithelium? A. GPCR activates adenylate cyclase generates CAMP opens CNG channel & depolarizes cell O B. GPCR activates adenylate cyclase generates CAMP opens calcium channel & depolarizes cell C. GPCR activates phospholipase C (PLC) cleaves PIP2 to generated DAG and IP3, DAG opens TRPC2 and depolarizes cell D. GPCR activates adenylate cyclase generates CAMP closes potassium channel and depolarizes cell