This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematopoeisis: Basic concepts, Subject name: Pathology
[{'content': 'An 18-year-old man moves from sea level to an elevation of 2,400 m to train as a skier. The increased requirement for oxygen delivery to tissues at the higher elevation stimulates the synthesis of a renal hormone (erythropoietin), which targets hematopoietic stem cells in the bone marrow. Erythropoietin promotes the survival of early erythroid progenitor cells primarily through which of the following mechanisms? \nSelect and explain. \nA. Altered cell-matrix adhesion, B. Downregulation of p53, C. Enhanced glucose uptake, D. Inhibition of apoptosis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: - Recent studies indicate that erythropoietin promotes survival of early erythroid progenitor cells through inhibition of default apoptosis pathway. - Thus, this hormone rescues stem cells that are otherwise fated to undergo programmed cell death. - None of the other choices are known to control the expansion of hematopoietic stem cell colonies in bone marrow.', 'role': 'assistant'}]