Correct Answer: A

Rationale: The correct answer is A: B lymphocytes. B lymphocytes (B cells) are a crucial part of the adaptive immune system. They produce antibodies, which are proteins that specifically target and neutralize pathogens such as bacteria and viruses. T lymphocytes (choice B) are involved in cell-mediated immunity rather than antibody production. Macrophages (choice C) are phagocytic cells that engulf and digest pathogens but do not produce antibodies. Neutrophils (choice D) are a type of white blood cell that primarily function in the innate immune response by phagocytosing pathogens.

Correct Answer: A

Rationale: Administering oxygen via face mask is the priority nursing action in a post-operative client suspected of a pulmonary embolism. This intervention helps ensure adequate oxygenation while further assessments and interventions are initiated. Elevating the client's legs is not indicated for a suspected pulmonary embolism; it is more appropriate for conditions like shock. Immediate surgery is not the priority in this situation as the client is experiencing acute symptoms requiring prompt intervention. While notifying the healthcare provider is important, the immediate focus should be on providing oxygen to the client to support respiratory function.

Correct Answer: C

Rationale: The correct answer is C. High evening glucose levels indicate that the morning dose of NPH insulin may be insufficient to control blood sugar throughout the day. Choice A is incorrect as cold and numb feet are more indicative of a circulation issue rather than an insulin inadequacy. Choice B suggests a wound infection rather than inadequate insulin. Choice D, nausea in the morning, may be due to other causes and does not necessarily indicate inadequate insulin dosage.

Correct Answer: B

Rationale: The correct answer is B: Airborne isolation. Measles is highly contagious and can be transmitted through airborne particles, so airborne isolation is necessary to prevent its spread. Choice A, Contact isolation, is incorrect because measles is not primarily transmitted through direct contact. Choice C, Droplet isolation, is also incorrect as measles is not transmitted through large droplets but through smaller airborne particles. Choice D, Reverse isolation, is used to protect a patient from outside infections, not to prevent the spread of a contagious disease like measles.

Correct Answer: B

Rationale: The correct answer is B: Ensuring the tracheostomy ties are secure. This is the nurse's first priority because it is critical to prevent accidental decannulation, which could compromise the patient's airway. Providing humidified oxygen, suctioning the tracheostomy tube, and monitoring for signs of infection are important aspects of care but ensuring the tracheostomy ties' security takes precedence to maintain the patient's airway.