Why option 4, not 3?
Please find below the answer:
There must be some issue with the answer key. In the given question, option (3) seems to be more correct. We will understand the same step by step:
If most of the males in a pedigree chart are affected by the trait, then it is assumed that the trait is sex-linked. If the ratio of presence of the trait in males and females in a pedigree chart is 1:1, then the trait is said to be autosomal. Since females also show the trait in the above pedigree, we can conclude that it is an autosomal trait.
If any one of the parents is showing the trait, it means the trait is dominant. But if none of the parents is showing the trait but it is present in children means the trait is recessive and the parents are carrying it.