The correct option is
D All of the above
Xylem is one of the types of complex permanent tissue which form the conductive part in plant body. It conducts mineral salt and water from roots to upper region. Primary xylem is the xylem, that is formed during primary growth from procambium. It includes protoxylem and metaxylem. Metaxylem develops after the protoxylem but before secondary xylem. Therefore, the correct answer is option D.