Answer:always present, they are inaccessible.
Explanation:
It's best if everyone would do some kind of exercise for at least 30 minutes on most, if not all, days.
Exercising at least 30 minutes every day by riding a bicycle, walking, doing calisthenics, gardening, or other activity is recommended.
The US Department of Health has found that daily exercise of some kind for at least 30 minutes a day will result in a healthier public.
Do at least 30 minutes of exercise, like brisk walking, most days of the week.
The answer is (C), becuse the reader does not now was is threatening the characters lives. In the other answers it told "it" was thereatening their lifes. This is why (c) has the sentence fragment.