Correct Answer: B

Rationale: The recommended time for introducing solid foods into an infant's diet is around 6 months of age. Introducing solids too early can increase the risk of food allergies and digestive issues, while waiting too long may lead to nutritional deficiencies. By around 6 months, most infants have the necessary physical and developmental skills to start eating solid foods alongside breast milk or formula.

Correct Answer: C

Rationale: Folic acid is the most critical nutrient for preventing neural tube defects during pregnancy. Neural tube defects are serious birth defects of the brain and spinal cord. Adequate intake of folic acid before and during early pregnancy can significantly reduce the risk of these defects. Iron, calcium, and vitamin D are important nutrients during pregnancy for other reasons, such as supporting the increased demands on the body for blood production, bone health, and calcium absorption, respectively.

Correct Answer: C

Rationale: The primary focus of the Integrated Management of Childhood Illness (IMCI) strategy is the prevention and treatment of major childhood illnesses. The IMCI strategy aims to reduce child mortality and morbidity by emphasizing a holistic approach that includes preventive measures along with curative interventions.

Correct Answer: D

Rationale: Integrated Management of Childhood Illness (IMCI) is a strategy developed by WHO and UNICEF. The key components of IMCI include integrated case management of childhood illnesses, where healthcare providers are trained to assess, classify, and treat common childhood illnesses holistically. This approach aims to improve the quality of care for children under five years of age by focusing on overall health, nutrition, immunization, and family and community practices. Therefore, promoting hospital-based care, providing routine immunizations, and enhancing maternal nutrition, while important, are not the sole key components of the IMCI strategy.

Correct Answer: C

Rationale: Malaria is caused by the Plasmodium parasite that is transmitted to humans through the bite of infected Anopheles mosquitoes. These mosquitoes act as vectors in transmitting the disease from one host to another. The other choices, Measles, Tuberculosis, and Hepatitis B, are not vector-borne diseases. Measles is a highly contagious airborne viral infection, Tuberculosis is an airborne bacterial infection, and Hepatitis B is a bloodborne virus.