Final answer:
When responding appropriately to cultural diversity, a phlebotomist should be sensitive to the patients' reactions.
Step-by-step explanation:
When responding appropriately to cultural diversity, a phlebotomist should be sensitive to the patients' reactions (option C). This means being aware of and respectful towards the cultural practices, beliefs, and preferences of patients from different backgrounds. It is important to understand that every patient is unique and may have specific cultural considerations that need to be taken into account during the interaction. Stereotyping patients (option B) is not appropriate as it can lead to biases and prejudices. Speaking in the patients' native language (option A) can be helpful if the phlebotomist is fluent, but it is not always necessary or practical in every situation. Quickly examining the patients' arm (option D) is an essential part of the phlebotomy procedure, but it is not directly related to responding to cultural diversity.