How can the complementation test discriminate between two viruses that have a mutation in the same ...

How can the complementation test discriminate between two viruses that have a mutation in the same gene versus two viruses that have mutations in the same gene?
 
  A. If the viruses have mutations in the same gene then, depending on the assay, a significant number of plaques will be produced or a significant number of plaques will have a wildtype phenotype. If the mutations are in the different genes few, if any, wild type plaques will be seen..
  B. If the viruses have mutations in different genes then, depending on the assay, a significant number of plaques will be produced or a significant number of plaques will have a wildtype phenotype. If the mutations are in the same gene few, if any, wild type plaques will be seen
  C. If the mutations are in the same gene the complementation test will result in recombinant viruses that are wildtype but if the mutations are in different genes no recombinant viruses will be produced.
  D. If the mutations are in different genes the complementation test will result in recombinant viruses that are wildtype but if the mutations are in the same gene no recombinant viruses will be produced.