At a Hospital in 1998,674 Women Were Diagnosed with Breast

At a hospital in 1998,674 women were diagnosed with breast cancer.Five years later,88% of the Caucasian women and 83% of the African American women were still alive.Determine the nature and scope of the conclusion the study can reach.

A) Since there is no random assignment,there is no way to know that being Caucasian causes women with breast cancer an increased chance of surviving five years; there may have been lurking variables.
B) For Caucasian and African American women with breast cancer,attending St.Luke's hospital causes an increased chance of surviving five years.
C) Since there is no random assignment,there is no way to know that being Caucasian causes women with breast cancer an increased chance of surviving five years; there may have been confounding variables.
D) Since the study is limited to Caucasian and African American women,no conclusion can be reached.
E) For women with breast cancer,being Caucasian causes an increased chance of surviving five years.