If you only draw a dashed red arrow from an argument to B) you only
say something like "This argument should be reconstructed in a way
that its conclusion contradicts B)". But your arrow will not affect
any other arguments or sentences.
This is useful if you want to create a first draft of an argument map
without getting into the details. As soon as you begin to reconstruct
the premise-conclusion structures within arguments, you should replace
dashed arrows with solid ones.
For more about logical relations, please read "Map-independent
definition of sentence relations" in the documentation.
http://www.argunet.org/working-with-argunet/ch01s02.html
regards,
christian