The silent killer is
a. coronary artery disease.
c. anemia.
b. arteriosclerosis.
d. hypertension.

The answer is letter D.

Hypertension or high blood pressure is one of the common chronic diseases that individuals have all over the world. It is a disease in which the pressure of the blood inside the blood vessels is higher than it should be. About 1 in 3 US adults have hypertension. It is known to be the silent killer because it has no known warning signs and symptoms. Often, a person with hypertension will develop heart diseases and even stroke. Hypertension can be prevented if a person chooses to eat healthily and exercises regularly. 

explanation:

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.