The correct option is
A Embryonic axis
The cotyledons are attached to the curved
embryonal axis (Tigellum) at the cotyledonary node. The micropylar end of the embryonal axis is rod-shaped and slightly bulged. It is called a radicle (or embryonic root). The other side of the embryonal axis lies in between the two cotyledons. It is called plumule( or the shoot tip).
So, the correct answer is option A.