There are four different human blood types: O, A, B and AB. The relationships between donor and recipients for these blood types are as follows: Type O can donate blood to any type. Type AB can receive blood from any type. Each type can donate blood to its own type. Each type can receive blood from its own type. Which one of the following donor-recipient bipartite graphs correctly represents this information? A B AB donor recipient NHL B O A B AB donor C 0 A B AB donor recipient recipient XXX B AB 0 A BAB OA B AB D A B AB donor recipient ENN EWM O A BAB OABAB E A BAB donor recipient

There are four different human blood types: O, A, B and AB. The relationships between donor and recipients for these blood types are as follows: Type O can donate blood to any type. Type AB can receive blood from any type. Each type can donate blood to its own type. Each type can receive blood from its own type. Which one of the following donor-recipient bipartite graphs correctly represents this information? A B AB donor recipient NHL B O A B AB donor C 0 A B AB donor recipient recipient XXX B AB 0 A BAB OA B AB D A B AB donor recipient ENN EWM O A BAB OABAB E A BAB donor recipient