Use the Following Commercial to Answer the Question(s) Below: a Recent

Use the following commercial to answer the question(s) below: A recent commercial advertised for a wristband that claimed to restore health and balance by taking advantage of natural frequencies of your biofield.It supports its claim by showing several people first struggling to balance without the wristband and then balancing fine with the wristband.
-Which of the following is a potential problem with the information presented?

A) There was a small sample size (only a few people presented) .
B) There were no control groups presented.
C) There was no indication that the results were repeated.
D) All of the above are potential problems with the information presented.