A 63-year-old woman says, I want to take estrogen to prevent AD, but my doctor won't prescribe it. ...

A 63-year-old woman says, I want to take estrogen to prevent AD, but my doctor won't prescribe it. Select the nurse's most informative response.
 
  a. Perhaps you should seek a second opinion. Estrogen clearly provides protection against AD.
  b. Most researchers now believe that estrogen is not actually deficient after menopause. It simply works in different ways.
  c. Most online resources indicate that estrogen provides important protection against development of AD.
  d. There is conflicting evidence about whether estrogen prevents Alzheimer's disease, but research clearly shows cardiovascular problems with estrogen therapy.