**Core Concept**
Bulimia nervosa is a type of eating disorder characterized by episodes of binge eating followed by compensatory behaviors, such as self-induced vomiting or laxative abuse, which can lead to normal weight despite the presence of disordered eating. This condition is distinct from anorexia nervosa, which typically results in weight loss due to restrictive eating and excessive exercise.

**Why the Correct Answer is Right**
Bulimia nervosa is correctly identified as the eating disorder with normal weight because individuals with this condition often engage in compensatory behaviors that counteract the caloric intake from binge eating episodes. This can lead to weight stability or even normal weight, despite the presence of disordered eating. The binge-purge cycle in bulimia nervosa can be driven by the activation of the hypothalamic-pituitary-adrenal (HPA) axis, which regulates stress response and appetite.

**Why Each Wrong Option is Incorrect**
**Option A:** Anorexia nervosa is characterized by restrictive eating patterns and excessive exercise, leading to significant weight loss, not normal weight.

**Option C:** Binge eating disorder is characterized by recurrent episodes of binge eating without compensatory behaviors, leading to weight gain and obesity in most cases.

**Option D:** This option is incorrect because bulimia nervosa is indeed an eating disorder that can present with normal weight.

**Clinical Pearl / High-Yield Fact**
A key feature of bulimia nervosa is the presence of "loss of control" during binge eating episodes, which can be a critical diagnostic clue for clinicians. This sense of loss of control can be related to the activation of the brain's reward system, which is driven by the release of dopamine and other neurotransmitters.

**✓ Correct Answer: B. Bulimia nervosa**