Final answer:
In medicine, "prn" stands for "pro re nata," which means "as needed." This indicates that the patient should take medication only when necessary.
Step-by-step explanation:
In medicine, "prn" stands for "pro re nata," a Latin phrase that means "as needed." When this is written on a prescription label, it indicates that the patient should take the medication only when necessary or as symptoms arise.
Out of the given options, any patient can have "prn" written on their prescription label, depending on their specific medical needs. Therefore, the correct answer is that all of the patients could potentially have "prn" written on their prescription labels.