A Nurse Is Observing as a Medical Student Places a Central

A nurse is observing as a medical student places a central line. The nurse notes that the medical student's tie is touching the sterile field. The best action by the nurse is to

A) Refrain from saying anything because the sterile field may not really be contaminated.
B) Wait until the procedure is over to inform the medical student that his tie brushed the sterile field.
C) Ask the medical student to stop the procedure immediately.
D) Suggest that the medical student not touch that side of the field.