The Babinski Sign Occurs When

Multiple Choice

 The Babinski sign occurs when

A) stroking the sole of the foot causes the toes to spread and the big toe to point upward.
B) stroking the sole of the foot causes the toes to curl and then separate.
C) tapping the knee with a small hammer causes the foot to kick.
D) both extensors and flexors at a joint contract simultaneously in violation of reciprocal inhibition.