In angiosperms, xylem is made up of

A

Tracheids and vessels

B

Vessels and fibres

C

Tracheids and fibres

D

All the above

The most distinctive xylem cells are the long tracheary elements that transport water. Tracheids and vessel elements are distinguished by their shape; vessel elements are shorter, and are connected together into long tubes that are called vessels. Xylem also contains two other cell types: parenchyma and fibers. 
So, the correct answer is 'All of the above.'