Correct Answer: C

Rationale: The correct answer is C: Cryptosporidium parvum. This parasite is the most likely cause of the infection due to its presentation with watery diarrhea, abdominal cramps, and nausea after consuming contaminated water. Laboratory tests revealing oocysts in the stool sample further support this diagnosis as Cryptosporidium parvum is known to produce oocysts in the stool. Giardia lamblia (choice A) presents with similar symptoms but does not typically produce oocysts. Entamoeba histolytica (choice B) is more associated with bloody diarrhea and liver abscesses. Cyclospora cayetanensis (choice D) is also associated with watery diarrhea but is less common in this scenario. Thus, based on the symptoms and laboratory findings, Cryptosporidium parvum is the most likely culprit.

Correct Answer: B

Rationale: The correct answer is B: Smoking cessation. Smoking is the leading cause of lung cancer, so quitting smoking is crucial in preventing and improving survival rates. Smoking cessation reduces the risk of developing lung cancer and improves treatment outcomes. High-dose chemotherapy (A) may be part of the treatment plan, but quitting smoking is more impactful. Early bronchoscopy (C) and early detection (D) are important, but without addressing the root cause (smoking), the survival rates will not significantly increase.

Correct Answer: D

Rationale: The correct answer is D: Subarachnoid hemorrhage. This condition presents with sudden-onset severe headache, vomiting, and altered mental status due to bleeding in the subarachnoid space. This type of hemorrhage is typically noncontrast-enhancing on imaging. A: Ischemic stroke does not typically present with sudden-onset severe headache and vomiting. B: Subdural hematoma usually presents with a slower onset of symptoms and often develops after head trauma. C: Intracerebral hemorrhage presents with focal neurological deficits rather than altered mental status and vomiting. In summary, based on the sudden onset of symptoms, imaging findings, and clinical presentation, subarachnoid hemorrhage is the most likely diagnosis in this case.

Correct Answer: C

Rationale: The correct answer is C because checking the completeness of the charting by doctors and nurses ensures that all necessary information is accurately documented, facilitating proper patient care and treatment. This step helps identify any missing or incorrect information that may impact patient safety. A: Storing the charts in respective shelves is a routine task that does not involve verifying the accuracy or completeness of the information. B: Separating medico-legal charts is important but does not directly address the completeness of charting by doctors and nurses. D: Binding the charts immediately is not necessary before ensuring the completeness and accuracy of the information documented.

Correct Answer: B

Rationale: The correct answer is B: Administer opioid analgesics to alleviate abdominal pain and discomfort. Opioid analgesics are effective in managing severe pain associated with malignant bowel obstruction. By providing adequate pain relief, the patient's comfort and quality of life can be significantly improved. Choice A is incorrect because initiating bowel rest and maintaining the patient in a semi-Fowler's position may not effectively address the severe pain and discomfort experienced by the patient. Choice C is incorrect as surgical intervention in this scenario may not be appropriate or feasible due to the advanced stage of cancer and the presence of malignant bowel obstruction. Choice D is incorrect as antiemetic medications primarily target nausea and vomiting, which may not be the primary symptoms of concern in this case. Focusing on pain management should be the priority.