The correct option is B Antigonon
In Antigonon leptopus, the main tendrillar and axillary branch is a modified inflorescence axis. It usually bears 67 lateral bracts out of which 34 lower ones are small and leaf-like while the upper 23 are tendrillar, 23 tendrils are also present at its terminal end. The floral buds arise in the axils of the bracts and bract-tendrils. No flowers are present in the axils of terminal bract-tendrils.
Thus, the correct answer is option A.