The correct option is D Caffeine
The World Anti-Doping Agency (WADA) issues list on revision basis that mentions list of prohibited substances by athletes. These substance may be completely prohibited, prohibited during competion only, etc.
Some of these substances are anabolic androgen steroids, erythropoietins, growth hormone, and their related analogues, all synthetic cannabinoids that mimic the effects of THC are prohibited.
Caffeine is currently in the monitor list and not yet prohibited. But between 1984-2004, the World Anti-Doping Agency (WADA) banned high concentrations of caffeine from all Olympic events.