All of these
The companion cells on the other hand are special parenchyma cells seen in flowering plants. These are attached to each sieve tube and are involved in the function of flow of nutrients.
The sieve tube elements are elongated, specialized cells in the phloem tissue of flowering plants whose ends are connected with other sieve tube members together constituting the sieve tube.
Conducting cells of xylem are treachery elements which are the constituents of tracheids and vessels. These are typically involved in the transportation of water and also in structural assistance. The conducting cells in xylem are elongated and narrow tracheids and even the vessel elements.
So, treachery elements is the correct option.
Read related NEET Questions at NEET BYJU’S.