What does the $i$ gene encode in the $lac$ operon?

In the $lac$ operon,which gene is responsible for coding the repressor protein?

Which gene produces the lactose repressor?

The $Lac-Operon$ model was elucidated by

If $E. coli$ is grown in a culture medium containing both glucose and lactose as carbon sources,when will its $lac$ operon be in the 'switch on' state?

Which of the following switches off the $lac$ operon?