Correct Answer: C

Rationale: A white blood cell count of 2,000/mm3 is low and indicates leukopenia, which increases the client's risk for infection. Hemoglobin level and platelet count are not directly indicative of infection risk. Serum creatinine level is related to kidney function, not infection risk.

Correct Answer: B

Rationale: Taking calcium supplements with meals is a crucial instruction for a client with osteoporosis. Calcium absorption is enhanced when taken with food, and proper calcium intake is essential for managing osteoporosis effectively by promoting bone health and density. Avoiding weight-bearing exercises (Choice A) is incorrect because these exercises help improve bone strength. Limiting vitamin D intake (Choice C) is also incorrect as vitamin D is necessary for calcium absorption. Increasing caffeine intake (Choice D) is not recommended as caffeine can interfere with calcium absorption.

Correct Answer: B

Rationale: A serum potassium level of 2.8 mEq/L is critically low and can cause cardiac arrhythmias, requiring immediate intervention. Hypokalemia is a life-threatening condition that needs prompt correction to prevent serious complications. High serum glucose levels (choice A) are a concern in diabetes but do not pose an immediate life-threatening risk compared to severe hypokalemia. Serum sodium (choice C) and serum bicarbonate levels (choice D) are within normal ranges and do not require immediate intervention.

Correct Answer: B

Rationale: Initiating short, frequent contacts with the client is the most appropriate action to promote trust. This approach helps build trust and rapport, addressing the client's need for security. By maintaining regular contact, the nurse can provide reassurance and support, which can help alleviate the client's anxiety related to her delusional beliefs. Choice A does not directly address the client's need for trust and security. Choice C focuses on the client's illness but does not actively address building trust. Choice D, offering to keep the belongings at the nurse's desk, may not be well-received by the client and could potentially worsen her anxiety and distrust.

Correct Answer: C

Rationale: Clear lung sounds indicate that the antibiotics are effectively treating the bacterial pneumonia by resolving the infection and reducing the inflammation in the lungs, leading to improved air exchange and ventilation. Increased respiratory rate (Choice A) and decreased oxygen saturation (Choice B) are indicative of ongoing respiratory distress and ineffective treatment. Elevated white blood cell count (Choice D) suggests a persistent infection rather than effective treatment.