Answer:
The correct answer would be - medium with lactose present and glucose absent.
Explanation:
There are genes present in lac operon that takes part in the lactose metabolism. These genes expressed only if a medium has lactose in absence of glucose.
In the absence of glucose and lactose is present, due to inducer the lac repressor is removed from the operator. This leads to the binding of CAMP to DNA as the CAMP levels are high. It helps in high transcription levels b binding RNA polymerase to promotor.