What blood type would likely result in an ABO typing of mixed-field?

The ABO typing of mixed-field occurs when there is a mixture of two different populations of red blood cells, which can be due to the presence of subgroups. In the case of the A3 subgroup, the red blood cells may possess characteristics of both the A antigen and antigen-negative cells, leading to a predominance of A antigen cells along with a small population of A-negative cells. This results in a mixed-field appearance during blood typing.

The mixed-field reaction is particularly evident in subgroup A3 as it is known to display relative weak expression of the A antigen, which can cause the formation of mixed fields upon serological testing. The mixed appearance more likely comes from a mixture of strong type A cells and cells that do not react significantly in the presence of anti-A antibodies.

In contrast, the other options do not prominently exhibit a mixed-field reaction. The B subgroup and the AB subgroup generally do not lead to mixed-field reactions because the respective antigens are typically expressed more consistently within those subgroups. The O subgroup lacks A or B antigens, which further removes the possibility of producing a mixed-field result.