California Registered Dental Assistant (RDA) Written Practice Exam

During a medical procedure, there are different designated areas for different roles. The clock concept states that certain instruments should be exchanged in a specific zone depending on the role of the person using them. In this case, the correct answer is A - the transfer zone. This is because the transfer zone is the area closest to the sterile field where sterile instruments can be exchanged between the sterile team members. The other options, such as the operator zone, assisting zone, and preparation zone do not specifically refer to the transfer of instruments and therefore would not be the appropriate zones to exchange instruments according to the clock concept. It's crucial to follow this concept to maintain a sterile environment and prevent contamination during the procedure.