A Highly Skilled Typist Can Type 120 Words Per Minute

Multiple Choice

A highly skilled typist can type 120 words per minute only because

A) the neural circuits responsible for activating each key press become active before the preceding key press has been completed.
B) different neural circuits at the lower levels of the sensorimotor hierarchy can be simultaneously active without interfering with one another.
C) the key presses have been chunked.
D) all of the above
E) he receives flowers from his boss at least once a month.