45 Officials across the country have been busying themselves with what until three or four years ago would have been an unthinkable task: persuading migrants to stay.
(A) All officials of the country have been busy with a vital task they should have done three years ago: persuading migrants to stay.
(B) Officials of the country have been busy persuading migrants to stay, which would have been unthinkable three or four years ago.
(C) Not until three or four years ago did the officials across the country think of the remarkable task: persuading migrants to stay.
(D) Officials of the country have been trying hard to ask migrants to stay, which won’t be done until three or four years from now.