Correct option is B
Explanation-
From the pedigree chart -
Parents:
Mother: Unaffected (white circle)
Father: Unaffected (white square)
Children:
Daughter: Affected (black circle)
Son: Affected (black square)
Interpretation:
Both parents are unaffected, yet both children (a son and a daughter) are affected. This rules out dominant inheritance, because if the trait were dominant, at least one parent would have to be affected to pass the trait.
This pattern fits recessive inheritance better, especially Autosomal Recessive Inheritance
Both parents are unaffected carriers (heterozygous: Aa).
Each child has a 25% chance of being affected (aa).
Both sons and daughters can be equally affected — no sex bias.
Incorrect options-
Options a – X-linked Recessive
More common in males than females.
Affected daughter from unaffected parents is very unlikely, unless the father is affected — which he isn’t.
Option c - X-linked Dominant
An affected daughter would require an affected parent — not the case here.
Again, both parents are unaffected, so this is ruled out.
Option d - Autosomal Dominant
At least one parent must be affected to pass the dominant allele. Neither parent is affected here.
So, the correct answer is option b – Autosomal Recessive.
