<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 2-week-old boy is brought to the emergency department after he was found to have blood in his stool. The mother says the baby was born by home birth at 38 weeks without complications. The mother denies fever, vomiting, or rash but says the baby has been fussier recently. The mother denies a family history of any similar problems. On exam, the patient is well-developed and meets all developmental markers. His heart rate is tachycardic but with regular rhythms. There is oozing blood from the umbilical site which has not fully healed. A guaiac stool test is positive. What is the underlying cause of this presentation?? A: Factor VIII deficiency, B: Bacterial infection, C: Factor IX deficiency, D: Vitamin K deficiency, E: Vitamin B12 deficiency,  <response>: This is a 2-week-old baby boy who is presenting with bloody stools. The key findings in the history are that he was born at home by normal vaginal delivery at 38 weeks, he has been fussier recently, and there is no family history of similar problems. On exam, he is well-developed but has tachycardia and oozing blood from the umbilical stump. A guaiac stool test was positive, confirming the presence of blood in the stool. The most likely diagnosis in a newborn with bloody stools and no family history of bleeding disorders is vitamin K deficiency. Vitamin K is necessary for the production of clotting factors II, VII, IX, and X. Newborns are at risk for vitamin K deficiency because vitamin K does not cross the placenta well and breastmilk is a poor source of vitamin K. Vitamin K deficiency can lead to hemorrhage. Home births and breastfeeding without vitamin K supplementation increase the risk. The other answer choices can be ruled out based on the clinical presentation.D: Vitamin K deficiency 