Which one of the following when added to a culture of non-encapsulated pneumococci derived from a type 1 strain will result in biosynthesis of type 3 polysaccharide?
a. Bacteriophage specific for type 3 strain
b. DNA extracted from virulent type 3 strain
c. Killed rough mutants from type 3 strain
d. Specific opsonin against type 3 strain
e. Type 3 polysaccharide

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