Final answer:
The first action a CNA should take upon resident admission is to introduce themselves and establish rapport with the resident, as this lays the foundation for effective communication and care.
Step-by-step explanation:
Upon resident admission in the facility, the first action a Certified Nursing Assistant (CNA) should take is B. Introduce themselves and establish rapport with the resident. Establishing a therapeutic relationship with the resident by introducing oneself and explaining roles when providing direct supervision is crucial for effective communication and care. Verifying the resident's identification and checking for allergies, reviewing medical records, and performing an initial health assessment are all important steps, but building rapport takes priority in order to help the new resident feel welcomed and comfortable.