The correct option is
C Ephedra
Gnetophytes are the most distinctive of gymnosperms because of their similarities with angiosperms. They have flower-like compound strobili. They have vessels in secondary xylem. They have double fertilization (However, this double fertilization does not result in the formation of endosperm. Instead, the diploid cell from fertilization by the second sperm disintegrates). There are 3 clearly defined, morphologically dissimilar genera of these gymnosperms: Ephedra (40 spp.), Gnetum (30 spp.), and Welwitschia (1 sp). One feature they all share, in addition to being gymnosperms, is the presence of vessel elements in their wood, a cell type absent in other gymnosperms.
So, the correct answer is option A.