The following pedigree shows the inheritance of an unknown disease "Z" in a family. Examine the pedigree carefully and choose which of the following best explains the inheritance of the disease "Z" in the individuals of the III generation.

• A. III - 1,2,3: Unaffected & III - 4,5,6: Affected
• B. III - 1,2,3: Affected & III - 4,5,6: Unaffected
• C. III - 1,2,3: Affected & III - 4,5,6: Affected
• D. III - 1,2,3: Unaffected & III - 4,5,6: Unaffected

Answer: (B)