Final answer:
Expressed consent refers to what is commonly known as informed consent, which is when participants fully understand and agree to the procedures and risks before participating in an experiment or medical procedure.
Step-by-step explanation:
Expressed consent is also known as A) Informed consent. This type of consent involves participants being fully informed about the procedures and risks involved in a research study or medical procedure before agreeing to participate or undergo the procedure. An informed consent form is often required in experiments, medical practices, and any other situation where an individual's acknowledgment and understanding of risks, benefits, and implications is necessary. Such consent may be given verbally or in writing, but typically, a written form is used to document the participant's comprehension and agreement. It includes details that ensure participants understand their rights and the voluntary nature of their involvement, that they can withdraw at any time, and it explains how their data will remain confidential.