Angela, Still Early in Her First Pregnancy, Is Surprised to See

Angela, still early in her first pregnancy, is surprised to see in an ultrasound image that her fetus's feet are the same size as its head. The ultrasound technician tells Angela that

A) this is an example of the caudocephalo principle of development
B) anterior (head) regions are usually bigger than and develop prior to posterior (feet) regions
C) prenatal development is often haphazard and does not usually follow any particular direction
D) this is an example of the proximodistal principle of development