Please help me to solve this pedigree ...........................

Since this is autosomal recessive trait inheritance pedigree so B will have “aa” genotype that is why B is able to express the phenotype in homozygous recessive condition.

Parent A can have AA or Aa genotype.

We can easily find that Parent A has genotype as AA because none of his/her progeny are showing the trait/disease.

if the parent A was Aa then he/ she should have 50% probabilty of affected progeny but that is not the case.

So option 1) is correct