On a Nursing Unit All Assigned Breaks Including Lunch/dinner Breaks

On a nursing unit all assigned breaks including lunch/dinner breaks are assigned at the beginning of the shift. A nurse caring for a patient with anemia and heart failure prepares to hang a unit of packed red blood cells and realizes her break is in 5 minutes. She decides it is not necessary to have another nurse check the blood against the patient's information since the patient's blood type is O+ which she incorrectly remembered to be the universal donor. She hangs the blood, noting the patient is "reading and vital signs normal." She leaves the floor for her break and does not report leaving or ask anyone to perform required vital signs. Upon returning she meets a family friend who is visiting and time "just flies." She returns to the patient's room after admitting a new patient. The patient is hypotensive and color is cyanotic and anxious. She reports the findings to the charge nurse, who then contacts the physician. A blood reaction occurrence is noted. The nurse providing care is charged:

A) with comparative negligence.
B) with a preventable adverse event.
C) with criminal negligence.
D) under the doctrine of res ipsa loquitur.