Research Has Shown That Women Who Were Exposed to the Flu

Research has shown that women who were exposed to the flu virus during the first trimester of pregnancy:

A) were not at risk for bearing a child who later developed schizophrenia.
B) had a sevenfold increased risk of bearing a child who later developed schizophrenia.
C) had only a slightly increased risk of bearing a child who later developed schizophrenia.
D) had a twofold increased risk of bearing a child who later developed schizophrenia.