Explain your reasoning for distributing the pints of

blood the way that you did.

Answer: There is no O - blood, so Patient 1 can only receive the B - pint.

There is no O - blood, so Patient 4 can only receive the O + pint.

The only remaining blood is B - and AB-.

Patient 2 can only receive the AB - pint.

Patient 3 can only receive the A + pint.