B is simply the Excelsior with a few new  front details. These hull additions were made so that the "damage"  caused by the Nexus ribbon would not require cutting into the actual  model. This miniature was seen first in  _Star Trek III: The Search for Spock (1984)_ (qv) and was used in  several episodes of _"Star Trek: The Next Generation" (1987)_ (qv)  and _"Star Trek: Deep Space Nine" (1993)_ (qv).