Company a Recently Acquired Another Company

Company A recently acquired another company. Users of the newly acquired company must be able to access a server that exists on Company A's network, both companies use overlapping IP address ranges. Which action conserves IP address space and provides access to the server?

A) Use a single IP address to create overload NAT
B) Use a single IP address to create a static NAT entry
C) Build one-to-one NAT translation for every user that needs access
D) Re-IP overlapping address space in the acquired company