Galactosemia commonly is due to deficiency of: (A) Galactose-1 phosphate uridyl transferase, (B) Galactose-1 phosphatase, (C) Glucose-1 phosphatase, (D) Glucose-6 phosphatase
Answer is A. Galactose-1 phosphate uridyl transferase 
Galactosemia is due to deficiency of :

Galactose-1-phosphate uridyl transferase (most common and best known),
Galactokinase, and
UDP-Galactose-4-epimerase.