Correct Answer: B

Rationale: The correct answer is B: 'Maternal stores of iron are depleted at about 6 months.' Iron deficiency anemia becomes apparent around 6 months of age when the infant's iron stores, primarily received from the mother during pregnancy, are depleted. This timing coincides with the introduction of solid foods, which may lack sufficient iron. Choices A, C, and D are incorrect because they do not address the specific reason why iron deficiency anemia is typically diagnosed around 6 months of age.

Correct Answer: B

Rationale: A positive correlation between two variables indicates that they move in the same direction. This means that as one variable increases (or decreases), the other variable also increases (or decreases). Choice A is incorrect because correlation does not imply causation; it only shows a relationship between variables. Choice C is incorrect as it describes a negative correlation where variables move in opposite directions. Choice D is incorrect as a positive correlation implies a relationship between the variables.

Correct Answer: B

Rationale: The correct answer is B: Strangulation of the hernia. Untreated inguinal hernias in children can lead to strangulation, which can result in bowel obstruction and ischemia. This is a serious complication that requires prompt medical attention. Choices A, C, and D are incorrect. Gastroenteritis is a gastrointestinal infection that is not directly related to untreated inguinal hernias. Chronic cough is not typically associated with this condition. Epistaxis refers to nosebleeds, which are not a common complication of untreated inguinal hernias in children.

Correct Answer: D

Rationale: In hypertrophic pyloric stenosis, an olive-shaped mass can often be palpated in the infant's abdomen, which is a hallmark sign of this condition. This mass is located in the right upper quadrant of the abdomen, right of the midline. Choices A, B, and C are incorrect because while infants with hypertrophic pyloric stenosis may experience vomiting (not diarrhea), gastric pain, and irritability, and have feeding difficulties, the key assessment finding specific to this condition is the palpable olive-shaped mass in the abdomen.

Correct Answer: B

Rationale: Encouraging frequent urination is a key preventive measure for avoiding urinary tract infections (UTIs) in children. It helps flush bacteria from the urinary tract, reducing the risk of UTIs. Restricting fluid intake (Choice A) is not recommended as it may lead to concentrated urine and increase the risk of UTIs. Using topical antibiotics (Choice C) is not a preventive measure for UTIs and should only be used under medical guidance. Increasing dietary calcium (Choice D) is not directly linked to preventing UTIs in children.