The correct option is C tracheary elements
Vascular cambium consists of two types of cells: fusiform initials and ray initials. The fusiform initials divide to form secondary phloem on the outer side and secondary xylem on the inner side. Secondary xylem includes xylem tracheary elements, i.e. xylem vessels and tracheids. The ray initials give rise to vascular rays or ray parenchyma. Primary phloem is formed by apical and intercalary meristems. Hence, the answer is tracheary elements.