Given below are two statements. One is labelled Assertion (A) and the other is labelled Reason (R).

Assertion (A) : The possibility of a female becoming haemophilic is extremely rare.

Reason    (R)  : Mother of such female has to be atleast carrier and father should be haemophilic.

In light of the above statements, choose the correct answer from the options given below.

Both (A) and (R) are true and (R) is the correct explanation of (A).  

Assertion (A) states that the possibility of a female becoming hemophilic is extremely rare, which is true. This is because hemophilia is an X-linked recessive disorder, meaning females need to inherit two copies of the mutated gene (one from each parent) to express the disorder. Since females have two X chromosomes, they would need to inherit a mutated copy from both their mother and their father, making it rare for them to be affected.

Reason (R) provides an explanation for Assertion (A) by stating that for a female to be hemophilic, her mother must be at least a carrier (heterozygous for the hemophilia gene) and her father should be hemophilic (having one mutated X chromosome). This combination increases the likelihood of a female inheriting two mutated copies of the gene. Therefore, Reason (R) correctly explains why the possibility of a female becoming hemophilic is extremely rare.