Final answer:
Informing a patient of a toileting schedule demonstrates unequal power in the nurse-patient relationship, as it removes some control from the patient.
Step-by-step explanation:
The action by a nurse that demonstrates unequal power in the nurse-patient relationship is c. informing a patient of a toileting schedule. This action can imply that the patient does not have control over basic bodily functions and must adhere to a schedule defined by the healthcare provider, representing a power imbalance. In contrast, actions such as administering an antibiotic as ordered, assisting a patient with personal care, and expressing empathy for a patient are seen as standard care practices and compassionate behavior that maintain equality and support in the nurse-patient relationship.