Select two correct statements from the four $(a-d)$ given below regarding the $lac$ operon.
$(A)$ Glucose or galactose may bind with the repressor gene and induce inactivity.
$(B)$ In the absence of lactose,the repressor binds with the operator region.
$(C)$ The $z$-gene codes for permease.
$(D)$ This was elucidated by Francois Jacob and Jacques Monod.
Which of the following are the correct statements?

• A
  $(B)$ and $(D)$
• B
  $(A)$ and $(B)$
• C
  $(B)$ and $(C)$
• D
  $(A)$ and $(C)$