A) Patients who have estrogen-sensitive breast cancer always metabolize the drug tamoxifen slowly.
B) Patients who have estrogen-sensitive breast cancer always metabolize the drug tamoxifen rapidly.
C) Patients who have estrogen-sensitive breast cancer have tumor cells that do not have estrogen receptors on their surface
D) Patients who have estrogen-sensitive breast cancer have tumor cells with estrogen receptors on their surface and the absence of estrogen in the body promotes the growth of the cancer.
E) Patients who have estrogen-sensitive breast cancer have tumor cells with estrogen receptors on their surface and the presence of estrogen in the body promotes the growth of the cancer.

A) only genetics.
B) only environmental factors.
C) both genetics and the environment.
D) the prenatal environment.
E) all of these.