This devastating disease usually appears in middle age with symptoms of clumsiness and forgetfulness. Now Dan's dad is still able to work, but his handwriting has become uncontrollable, and it is difficult for him to sit for long periods without twitching.Why does the writer mention that Dan's father's handwriting has become uncontrollable and that it is difficult for him to sit for long periods without twitching?

A. to show that Dan's father is suffering from Huntington's disease
B. to suggest that life is not that bad for people with Huntington's disease
C. to create an image of the disease in the reader's mind