A Promotional Video for a Mindfulness Retreat Shows People Walking

A promotional video for a mindfulness retreat shows people walking across hot coals while barefoot. The founder of the retreat says that by learning neurolinguistic programming you too can walk across hot coals and handle any stress. You should be skeptical about the effectiveness of neurolinguistic programming in this instance because

A) it is impossible to calmly walk over hot coals.
B) it is likely that this finding was tainted by observer bias.
C) correlation does not equal causation.
D) there was no control group with which to make a comparison.