Chantal has configured the network at her company's new headquarters with a number of VLANs. All devices joined to the individual VLANs appear to be tagging the traffic correctly. However, there are still some frames being transmitted across the network that are not tagged to any particular VLAN. Which of the following describes the term by which a switch will categorize these frames?
a. Management VLAN b. Data VLAN c. Native VLAN d. Voice VLAN