A patient who is complaining of a new onset of severe headache is being examined. The patient is instructed to lie down on the examining table while the nurse practitioner flexes his head and neck forward to his chest. The patient reacts by quickly flexing his hip and knee. What is the name of this positive finding?

A) Kernig's sign
B) Brudzinski's sign
C) Rovsing's sign
D) Drawer's sign