Asystemadministratorhasbeenaskedtomigratethedev_vgvolumegroupfromserverAtoserverB.Thedev_vgvolumegroupcontainsasinglefilesystemnamed"/development".Toprepareformigration，whichofthefollowingisthecorrectsequenceofcommandsforremovingthevolumegroupfromserverA？

Asystemadministratorhasbeenaskedtomigratethedev_vgvolumegroupfromserverAtoserverB.Thedev_vgvolumegroupcontainsasinglefilesystemnamed"/development".Toprepareformigration，whichofthefollowingisthecorrectsequenceofcommandsforremovingthevolumegroupfromserverA？（）

A.exportvgdev_vg；umount/development；varyoffvgdev_vg

B.varyoffvgdev_vg；umount/development；exportvgdev_vg

C.umount/development；exportvgdev_vg；varyoffvgdev_vg

D.umount/development；varyoffvgdev_vg；exportvgdev_vg