Why Is the Russian Government Constructing a Concrete and Steel

Why is the Russian government constructing a concrete and steel arch around the destroyed nuclear reactor in Chernobyl? A)because the Ukraine government wants to hide the object of so much destruction and death B)in hope of controlling the further spread of radioactive dust C)people want to return to the abandoned cities and towns closed by the initial reactor meltdown D)to stop curious tourists from wandering into the radioactive site E)to house a new museum dedicated to the disaster