A Client Receiving a Blood Transfusion Develops Anxiety and Low

A client receiving a blood transfusion develops anxiety and low back pain.After stopping the transfusion,what action by the nurse is most important?

A) Documenting the events in the client's medical record
B) Double-checking the client and blood product identification
C) Placing the client on strict bedrest until the pain subsides
D) Reviewing the client's medical record for known allergies