The right answer is B.
Miguel wants to learn doping to increase his muscle mass.
Doping involves taking stimulants to improve one's performance. Certain methods of doping are prohibited in sport unless a prescription justifies a medical reason for taking a drug. Among the banned molecules are for example:
anabolic agents, such as testosterone;
hormones and growth factors (EPO, insulin, growth hormone ...);
diuretics;
stimulants: amphetamine, cocaine ...