Final answer:
The characteristic of people with anorexia nervosa is an intense fear of gaining weight. This disorder involves restricted food intake and distorted body image, different from bulimia nervosa, which includes binge eating and purging.
Step-by-step explanation:
The characteristic of people with anorexia nervosa is C) Intense fear of gaining weight. Anorexia nervosa is an eating disorder where individuals restrict their food intake due to a fear of weight gain and often have a distorted body image. They may see themselves as overweight even when they are significantly underweight. Anorexia nervosa is also associated with a range of negative health outcomes and a preoccupation with food, despite the consumption of very little amounts. This contrasts with bulimia nervosa, which is characterized by episodes of binge eating followed by purging behaviours to compensate for food intake, aiming to prevent weight gain.