Final answer:
It is difficult to determine the exact percentage, but a significant portion of individuals with bulimia nervosa may struggle with abusing substances to control their appetite.
Step-by-step explanation:
Based on the information provided, it is difficult to determine the exact percentage of individuals with bulimia nervosa who will struggle with abusing alcohol or stimulants to control their appetite. However, it is mentioned that individuals with bulimia nervosa are at an increased risk for substance abuse. This suggests that a significant portion of individuals with bulimia nervosa may struggle with using substances to regulate their appetite. Therefore, option D. 60% is a possible answer.