Correct Answer: D

Rationale: The correct answer is D: Placental insufficiency. A bipartite placenta and succenturiate lobe are structural abnormalities that can lead to placental insufficiency. This is because these conditions can interfere with proper blood flow and nutrient exchange between the mother and fetus, resulting in decreased oxygen and nutrients reaching the fetus, leading to placental insufficiency. Placental abruption (choice A), placental calcification (choice B), and placenta previa (choice C) are not directly associated with bipartite placenta or succenturiate lobe and do not specifically cause placental insufficiency.

Correct Answer: D

Rationale: The correct answer is D, complete rupture of the uterus. This is an obstetric emergency due to the risk of severe bleeding and potential harm to both the mother and the fetus. A ruptured uterus can lead to life-threatening complications such as hemorrhage and shock. In contrast, options A, B, and C are not considered obstetric emergencies. Aftercoming head in breech, complete cephalic presentation, and complete breech presentation are normal variations in labor that do not typically require immediate intervention like a ruptured uterus does.

Correct Answer: A

Rationale: The correct answer is A (Low ACTH and low cortisol) because in patients with an adrenal tumor causing Cushing's syndrome, the tumor autonomously produces cortisol, leading to suppression of ACTH secretion from the pituitary. This results in low ACTH levels and high cortisol levels. Choices B, C, and D are incorrect because they do not reflect the characteristic hormone levels seen in patients with an adrenal tumor causing Cushing's syndrome.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Uterine atony is the most common cause of immediate postpartum hemorrhage due to inadequate uterine contraction to control bleeding. This is supported by research and clinical evidence. Trauma to the genital tract is a less common cause and usually leads to delayed hemorrhage. Choice B is incorrect as uterine atony is a well-documented primary cause. Choice C is incorrect as uterine atony is consistently the leading cause. Choice D is incorrect as the cause of immediate postpartum hemorrhage is clear, with uterine atony being the most common culprit.

Correct Answer: A

Rationale: The correct answer is A because high-volume liver resection is typically performed in individuals with significantly compromised hepatic function to ensure adequate liver remnant. Removing 50 to 75% of the liver in a patient with metastatic colon cancer may be necessary for tumor clearance but carries risks due to potential impairment of liver function postoperatively. Choices B and C provide inaccurate information regarding the timeline and extent of liver regeneration following resection. Choice D is incorrect as removing up to 95% of the liver would lead to severe consequences, such as liver failure. Hence, option A is the most appropriate advice given the patient's situation.