Given below is pedigree chart showing the inheritance of a certain trait in human. Select the correct option for the given chart

$A$ - Sickle-cell anaemia is sex linked recessive trait

$R$ - This disease is controlled by more that two pair of alleles

The most striking example of point mutation is found in a disease called

Haemophilia $A$ is due to the absence of

Choose correct option.

$(i)$ The heterozygous female transmit the disease to son.

$(ii)$ Change in the shape of the $RBC$ from biconcave disc to elongated sickle like structure.

$(iii)$ Mentally retarded.

$(iv)$ Heamoglobin not formed proper amount in blood.

Assertion : Haemophilia is a recessive sex linked disease.

Reason : Haemophilia occurs due to mutation of a structural gene on chromosome $15$.