This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: RH Incompatibility, Subject name: Gynaecology & Obstetrics
At 29 weeks gestational age a fetus has hydrops. All of the following are characteristics of fetal hydrops except 
Select and explain. 
A. Polyhydramnios, B. Small placenta, C. Pericardial effusion, D. Ascites
B: Small placenta
Answer: B: Small placenta 
Explanation: Fetal hydrops occurs as a result of excessive and prolonged hemolysis due to isoimmunization. Characteristics of fetal hydrops include abnormal fluid in two or more sites such as the thorax, abdomen, and skin. The placenta is also markedly erythematous, enlarged, and boggy. In addition, massive hepatomegaly and splenomegaly may be present.