First, to understand our results we must remember a little about how the tests and blood type works. We have two types of antibodies A and B, the absent phenotype is O, and the Rh that is another antibody. When we do a test, we use antiserums that will react to the presence of one of these two antibodies A and B, and it is characterized by agglutination of the drop of blood in the sample.
In the present case (Emma) seems in the photo, like there is no agglutination reaction which would be an O type, that is to say, it doesn't have A nor B antibodies, and accordingly to the exercise mother (Emily) and father ( Ernest) one is B and the other is A, so Emma wouldn't be their biological daughter, the likelihood is very low. The only possible genotype for someone O, is (OO) because is a recessive character.
A few notes: As far as it is visible on the photographs the blood doesn't look like there is an agglutination reaction, but it could be due to resolution, so it must be looked at carefully, nonetheless, when we see the next sample the one of Ernest it is possible to see agglutination if you look carefully at the A pit, it looks like there is a little of sand or some kind of residue, which is none other than the agglutination reaction, making Ernes positive for A antibody.