Final answer:
To ensure ethical research, John Watson's experiment should have obtained informed consent from participants and undergone an ethical review.
Step-by-step explanation:
In John Watson's experiment, it can be argued that the guidelines violated were B) Informed Consent and D) Ethical Review. Informed consent is the process of ensuring that participants are provided with information about the study, including its purpose, potential risks and benefits, and their rights as participants, and then giving them the opportunity to voluntarily agree to participate. Ethical review involves having the experiment reviewed by an institutional review board (IRB) to ensure that it meets ethical standards and protects the rights and well-being of participants.