A and C
Who, using your very best guess, do you think will pay for all of those secondary radar installations plus the hardware and software networks required to make them work and the training of everyone involved?
Lets not even get started on the cost of NATS monitoring your flights.
And would you have us believe that when an ATCO sits down at his screen, on a lovely Sunday morning, and sees a snow of numbers creeping around it, that he will not turn you off so that he can actually see the commercials that he is trying to get into Gatwick/Luton/Stansted/Heatrow/etc?