Option D is the one most accurately describing Lac Operon.
The lac operon is known as an inducible system. Since Lac operon is an inducible system, it will only activate in the presence of a key molecule . The key molecule, lactose, induces the Lac operon to be activated.
Once lactose binds to the repressor, it causes it to be removed. RNA polymerase is then able to access the genes in the Lac operon and transcribe them in RNA and eventually proteins.
Electrons are only located in specific shells or orbitals that surround the nucleus of an atom. Therefore, I believe that your answer would be true. Hope it helped some!
