MCQ- Antigen A

[Tyto alba]

Homework Statement

The terminal sugar moiety in the blood group substance A is

1) N-acetylgalactosamine
2) Fucose
3) Galactose
4) Glucose

(One right answer)
2. The attempt at a solution
I checked proteopedia it is Option 1 . I wonder why because both N-acetylgalactosamine and fucose are present as the terminal sugars on Galactose.