In Which Way Does an Individual Develop a Naturally Acquired

Multiple Choice

In which way does an individual develop a naturally acquired active immunity?

A) When antibodies from the mother cross the placenta to the fetus
B) When antibodies from the fetus cross the placenta to the mother
C) From immunization with antibodies to a disease-causing organism
D) From exposure to organisms that cause a disease
E) From administration of a vaccine with killed or weakened organisms