Which of the following abnormalities is due to an autosomal dominant mutation?

From the following pedigree chart of a family,one can make an analysis that:

$A$ woman with normal vision marries a man with normal vision and gives birth to a color-blind son. Her husband dies,and she remarries a color-blind man. What is the probability of color blindness in her children from the second marriage?

Choose the incorrect statement for haemophilia.

Assertion: Persons suffering from haemophilia fail to produce blood clotting factor $VIII$.
Reason: Prothrombin producing platelets in such persons are found in very low concentration.

Choose the correct option for the symptoms of $Phenylketonuria$ $(PKU)$.