Which of the following statements are true regarding VLANs? Each correct answer represents a complete solution.
a) VLANs are used to segment a network into multiple broadcast domains.
b) VLANs can improve network security by isolating traffic between different groups of devices.
c) VLANs operate at the transport layer of the OSI model.
d) VLAN membership is determined by physical location rather than logical grouping.