What factors contribute to cerebral blood pressure regulation?

Correct answer is D). Cerebral blood pressure is regulated by factors such as sympathetic nervous system activity, blood viscosity, and systemic vascular resistance. These elements collectively influence the perfusion of blood to the brain. A) Incorrect. Digestive processes, hormonal fluctuations, and kidney function are not primary factors in the immediate regulation of cerebral blood pressure. B) Incorrect. While heart rate and oxygen content in the blood can influence cerebral blood pressure, the concentration of cerebrospinal fluid is not a primary regulator. C) Incorrect. Temperature regulation and carbon dioxide levels play roles in cerebral blood flow regulation, but the number of red blood cells is not a direct contributor.