Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: The lacZ gene is present of pUC cloning vectors as the selectable market by which recombinants may be selected through insertional inactivation of lacZ gene.

Reason R: IPTG acts as gratuitous inducer of lacZ genes due to which recombinants produced in pUC vectors may be selected by Blue-white screening.

In the light of the above statements, choose the correct answer from the options given below: