The correct answer is (D) They lack DNA so they must use the DNA of the host cell.
Viruses have their own genetic material to replicate and they need not to use the genetic material for the their survival in host body. Growth and division is one of the important factors for the survival of the organism. The virus themselves have their genetic material RNA or DNA for replication. They just need a host body because they cannot synthesize protein. They cannot produce or store energy. They lack molecules like nucleotide and lipid.