The following diagram shows restriction sites in the $E. coli$ cloning vector $pBR322$. Identify the role of '$X$' and '$Y$' genes:

• A
  The gene '$X$' is responsible for controlling the copy number of the linked $DNA$ and '$Y$' for the protein involved in the replication of the plasmid.
• B
  The gene '$X$' is for the protein involved in the replication of the plasmid and '$Y$' is for resistance to antibiotics.
• C
  Gene '$X$' is responsible for recognition sites and '$Y$' is responsible for antibiotic resistance.
• D
  The gene '$X$' is responsible for resistance to antibiotics and '$Y$' for the protein involved in the replication of the plasmid.