If you put Anti-A antibodies with an unknown antigen and it agglutinates what type of blood is it?

If anti-A antibodies are added to an unknown antigen and agglutination occurs, it indicates that the unknown antigen is of blood type A. This is because anti-A antibodies specifically bind to and agglutinate antigens present on the surface of red blood cells of blood group A. The presence of agglutination confirms the presence of A antigens, hence the unknown antigen is identified as blood type A.