What is the role of the H antigen in the ABO blood group system?

A It is the precursor to the A and B antigens
B It is an enzyme that breaks down A and B antigens
C It is a protein that inhibits the expression of A and B antigens
D It is a carbohydrate that enhances the expression of A and B antigens
The H antigen is the precursor to the A and B antigens in the ABO blood group system. It is modified by enzymes to produce the A and B antigens.
Medical Microbiology by Jawetz
Hematology Hematology: Blood Grouping and Crossmatching Hematology: Blood Grouping and Crossmatching Medium MEDICAL Confidence: high