Final answer:
The most common method for restricting unauthorized access to EMRs is through the use of passwords. Fingerprints and retinal scans are also methods that can be used, but they are not as common. A combination of passwords and fingerprints may be used for enhanced security.
Step-by-step explanation:
The most common method for restricting unauthorized access to EMRs (Electronic Medical Records) is through the use of passwords. Passwords provide a level of security by requiring users to enter a unique combination of characters before gaining access to the EMR system. This method is commonly used because it is easy to implement and manage, and it allows authorized users to easily access the system.
Fingerprints and retinal scans are also methods that can be used to restrict unauthorized access to EMRs, but they are not as common as passwords. These biometric methods involve scanning a person's unique physical traits, such as fingerprints or the pattern of blood vessels in the retina, to verify their identity. While they offer higher levels of security, they are more complex and expensive to implement.
In some cases, a combination of passwords and fingerprints may be used to further enhance the security of EMRs. This means that both option a (passwords) and option b (fingerprints) are correct.