All are true about notochord except ?
A. Prenotochordal cells invaginating in the primitive pit move forward cephalad until they reach the prechordal plate.
B. The prechordal plate itself forms between the tip of the notochord and the buccopharyngeal membrane
C. Becomes annulus fibrosus of adult intervertebral disc
D. elongation of the notochord is a dynamic process