Six mutants in the rII region of phage T4 were independently isolated. Recombination to produce wild-type progeny occurred between all of these mutants. Pairwise multiple infections of E.coli strain K12 were made with the results shown below. (The number of phage particles used in each multiple infection was approximately the same, and was constant among experiments).

(a) Fill in a complementation table. Use “+” for complementation and “0” for no complementation.

(b) How many genes are affected among all these mutant strains?

(c) Which mutants have mutations in the same gene(s)?