Which of the following describes a woman at risk for breast cancer?

The identification of a woman at risk for breast cancer is significantly influenced by family medical history. A woman whose mother, sister, or daughter has had breast cancer falls into a higher risk category due to genetic factors and the hereditary nature of certain cancers. Familial connections to breast cancer often indicate inherited mutations such as BRCA1 or BRCA2 that substantially increase an individual’s risk toward developing the disease.

Factors like having no previous breast-related medical history or being under the age of 30 without any family history do not inherently denote an increased risk for breast cancer. Moreover, a woman who has undergone a double mastectomy typically does so as a preventive measure if she has a high familial risk or if she has previously had breast cancer, which means she may already be actively managing her risk rather than being at risk in the traditional sense.

Thus, the correct identification of option B underscores the importance of family history as a critical component in assessing a woman's risk for developing breast cancer.