If an Ouchterlony Immunodiffusion Pattern Shows an Arc Between Antigens

Multiple Choice

If an Ouchterlony immunodiffusion pattern shows an arc between antigens A and B with an extended line pointing to antigen B,this indicates that the antigens:

A) are identical.
B) are entirely different.
C) share a common epitope, with A being a more complex antigen.
D) share a common epitope, with B being a more complex antigen.