C. Viral infection
Step-by-step explanation:
Fetal bradycardia can be considered a later sign of fetal hypoxia and is known to occur before fetal death. Bradycardia can result from placental transfer of drugs, viral infections such as cytomegalovirus (CMV), maternal hypothermia, and maternal hypothermia. Maternal hyperthyroidism, fetal anemia, and tocolytic treatment using ritodrine will most likely result in fetal tachycardia.