Insertion of a gene at which of the following restriction sites of pBR322 does not result in insertional inactivation?

Insertional inactivation takes place when a gene is inserted at restriction site present within the marker gene/s. Pvu I and Pst I are present within the ampR region Sal I is present within tetR marker gene. EcoR I is not present within the marker genes. Hence if a gene is inserted at EcoR I site, there wont be insertional inactivation.