Correct Answer: B

Rationale: Increased urine output is a reliable indicator that hydration status is improving. While alertness and playfulness are positive signs, increased urine output directly reflects improved hydration. Stable vital signs are important but may not directly indicate hydration status. Tolerating small amounts of oral fluids is a good sign but may not be as direct an indicator as increased urine output.

Correct Answer: C

Rationale: The correct answer is C: 'Avoid giving any medication containing aspirin during a viral illness.' It is crucial to advise parents to avoid giving any medication containing aspirin during a viral illness to prevent Reye's syndrome. Reye's syndrome is a rare but serious condition linked to the use of aspirin during viral illnesses in children and teenagers. Choices A, B, and D are incorrect because vaccinating against Reye's syndrome is not applicable as there is no specific vaccine for it, keeping the child at home for 2 days after symptoms appear is not a preventive measure for Reye's syndrome, and avoiding citrus juices is not directly related to the prevention of Reye's syndrome.

Correct Answer: C

Rationale: A serum potassium level of 3.0 mEq/L is significantly low and indicates hypokalemia, which can lead to serious complications such as cardiac arrhythmias. Therefore, it is crucial for the nurse to report this finding promptly to the healthcare provider for immediate intervention. The other findings are not as critical in this situation. Gastric output of 100 mL in the last 8 hours may be expected in a patient with persistent vomiting. The shift intake of IV fluids and ice chips indicates fluid replacement, which is important but not as urgent as correcting electrolyte imbalances. A serum pH of 7.45 is within the normal range and does not indicate an immediate concern.

Correct Answer: B

Rationale: The correct answer is B. Infants should not be given cow's milk before 1 year of age as it can interfere with iron absorption and lead to anemia. Choice A is incorrect as avoiding sugary water is actually a good practice. Choice C is unrelated to iron-deficiency anemia. Choice D, not liking peaches or pears, is also not directly related to iron-deficiency anemia.

Correct Answer: C

Rationale: Chorea associated with rheumatic fever is usually temporary and will subside over time.