Correct Answer: A

Rationale: The correct answer is A: Sitting independently. By 11 months, most infants can sit independently. This milestone usually precedes walking, which typically occurs closer to 12 months. Turning a doorknob and building a tower of four cubes involve more complex motor skills that are typically achieved later in development. Therefore, at 11 months, sitting independently is the milestone that the nurse would expect an infant to have achieved.

Correct Answer: B

Rationale: Mortality statistics describe the number of individuals who have died over a specific period, providing insight into public health concerns.

Correct Answer: C

Rationale: The best approach is to discuss childcare options that would suit Eric's needs, allowing the mother to make an informed decision without guilt or pressure.

Correct Answer: D

Rationale: Family systems theory views the family as a whole, where changes in one member affect the entire system, and changes can occur at any point within the system.

Correct Answer: D

Rationale: The correct answer is D. Vaso-occlusive crises in sickle cell anemia are characterized by painful swelling of the joints in the hands and feet (hand-foot syndrome) and tissue engorgement due to the obstruction of blood flow by sickled cells. Choices A, B, and C are incorrect because circulatory collapse, hypovolemia, cardiomegaly, systolic murmur, hepatomegaly, and intrahepatic cholestasis are not typically associated with an acute vaso-occlusive crisis in sickle cell anemia.