Correct Answer: C

Rationale: The correct answer is IgM. IgM is the first antibody produced in response to an infection and is elevated in a fetus with an in utero infection. IgG is the primary antibody responsible for providing immunity to the fetus and is transferred across the placenta during the third trimester. IgA is mainly found in mucosal areas and colostrum but not significantly elevated in fetal infections. IgD is involved in the development and maturation of B cells but not typically increased in fetal infections.

Correct Answer: A

Rationale: When starting on oral contraceptives, it is crucial to take them at the same time each day to maintain consistent hormone levels and ensure effectiveness in preventing pregnancy. Choice B is incorrect because consistency in timing is essential for optimal efficacy. Choice C is inaccurate as oral contraceptives do not need to be taken with food for absorption. Choice D is incorrect because missing doses or skipping oral contraceptives can reduce their effectiveness in preventing pregnancy.

Correct Answer: C

Rationale: The correct answer is C: Mitral valve stenosis. Rheumatic fever can lead to scarring and thickening of the heart valves, often affecting the mitral valve. This stenosis can impede blood flow from the left atrium to the left ventricle, eventually causing heart failure. Choice A, infective endocarditis, is an infection of the endocardium, the inner lining of the heart chambers and valves, and is not directly related to rheumatic fever. Choice B, coronary artery disease, involves the obstruction of coronary arteries supplying the heart muscle with blood, leading to ischemia and not typically associated with rheumatic fever. Choice D, aortic regurgitation, is the backflow of blood from the aorta to the left ventricle and is not a common consequence of rheumatic fever.

Correct Answer: C

Rationale: The withdrawal reflex is a protective response that allows a person to quickly remove their hand from a painful stimulus.

Correct Answer: A

Rationale: In the treatment of tuberculosis, drug resistance commonly develops against medications like Isoniazid (INH) and rifampin. These two drugs are key components of the standard anti-tuberculosis treatment regimen. Choices B, C, and D are unrelated medications that are not used in the treatment of tuberculosis. Carbamazepine and phenytoin are anticonvulsants, dextroamphetamine is a stimulant, and propranolol and sotalol are used for cardiovascular conditions.