Which of the following most accurately describes hemophilia?

Examples of congenital diseases are

Assertion $(A) :$ Phenylketonuria is an inborn error of metabolism and inherited as the autosomal dominant trait.
Reason $(R) :$ The disease is caused by mutation in the gene that codes for the enzyme phenylalanine hydroxylase.

The female children of a haemophilic man and a carrier woman are likely to be:

Which of the following is a sex-linked character?

$A$ man and a woman,who do not show any apparent signs of a certain inherited disease,have seven children ($2$ daughters and $5$ sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following modes of inheritance do you suggest for this disease?