In which of the following scenarios would the defendant not be legally liable for negligence?

In the scenario involving Bill restoring an antique auto, the defendant is not deemed legally liable for negligence because there is typically no duty of care owed to the general public when one is engaging in an activity that does not foreseeably cause harm to others. Bill is likely taking on a private project with minimal risk to the public. Unlike scenarios where the actions directly affect others or involve known hazards, restoring a private antique vehicle generally does not engage liability unless there is reckless behavior or a failure to adhere to safety standards that impact others.

In contrast, the other options involve circumstances where an individual's actions might impact another person or create a foreseeable risk that leads to negligence. For example, a faulty walkway (Jack), a potentially dangerous purchase (Irene), or dropping a heavy object (Susan) all involve a clear duty of care and the potential for causing harm to others, thus establishing grounds for negligence.