The correct answer A - 'Attempt to access the device using the default credentials' is correct because many IoT devices come with default, hard-coded credentials that are often listed in user manuals or online resources, and attackers routinely exploit these. Accessing the device with these credentials can demonstrate how an attacker could gain unauthorized access easily. Option B is incorrect as hard coding does not necessarily mean susceptible to electromagnetic interference. Option C is less likely to be effective since hard-coded configurations might not be present in network signals. Finally, Option D is incorrect because conducting a factory reset would merely restore the device to its original state, which still includes the hard-coded configurations.