An organization has a compliancy requirement to protect servers from clients, however, the clients and servers all reside on the same Layer 3 network. Without readdressing IP subnets for clients or servers, how is segmentation achieved?

An organization has a compliancy requirement to protect servers from clients, however, the clients and servers all reside on the same Layer 3 network. Without readdressing IP subnets for clients or servers, how is segmentation achieved?
A. Change the IP addresses of the servers, while remaining on the same subnet.
B. Deploy a firewall in routed mode between the clients and servers.
C. Change the IP addresses of the clients, while remaining on the same subnet.
D. Deploy a firewall in transparent mode between the clients and servers.