What of the following is not characteristic of the pBR322 vector?

• A

  It has two antibiotic-resistance genes: amp^R and tet^R

• B

  It was the first artificial cloning vector constructed in 1997 by Boliver and Rodriguez.

• C

  The ampicillin-resistance gene has restriction sites for Pst l and Sal l

• D

  The restriction site for Pvu ll is present in the rop gene.