When People Try to Synchronize Foot and Finger Taps

When people try to synchronize foot and finger taps

A) The finger leads the foot by the amount of time one would expect if people could sense motor commands
B) The foot leads the finger by the amount of time one would expect if people could not sense motor commands but instead strove for simultaneous sensory signals from the foot and finger
C) The finger and the foot respond at exactly the same time, reflecting people's excellent timing abilities
D) For some people, the finger leads the foot and for other people the foot leads the finger, but no one knows why