cyst of the cavum Vergae

Q.All are true regarding pellucidum septum except

a. The double septum or fifth ventricle is due to the abnormal persistence of the fetal cavum septi pellucidi

b. cavum septi pellucidi  persists in 1-2% of adults

c. cyst of the cavum Vergae represents the so-called `sixth ventricle'

d.  cyst of the cavum Vergae  is backward expetion of  the septal cyst

e.  cyst of the cavum Vergae lies beneath the posterior part of corpus callosum with the velum interpositum above

ANS.----d

cyst of the cavum Vergae  lies beneath the posterior part of corpus callosum with the velum interpositum below