Final answer:
The main legal risk in using an AED is failing to deliver a shock when one is needed, which could arise from user error or device malfunction.
Step-by-step explanation:
The main legal risk in using an Automated External Defibrillator (AED) is C. failing to deliver a shock when one is needed. In the context of AED use, this could be due to either a user failing to follow the AED's instructions or a malfunction of the AED itself. As AEDs are designed for use by laypersons and provide automated instructions, the user must adhere to these prompts to minimize risks.
It is crucial to follow proper procedure, which includes providing CPR if necessary and allowing the AED to guide the rescuer in delivering a shock. Moreover, legal protection is often offered under Good Samaritan laws to individuals who assist those in medical distress with an AED.
Nonetheless, improper use leading to a failure to provide a necessary shock could increase the risk of harm to the patient and potentially expose the user to legal liability, especially if it is found that the user deviated from established emergency protocols or used the AED in a negligent manner. The correct answer is (c) failing to deliver a shock when one is needed.