Exercício: Right question to the given answer

Choose the best question for this sentence: "In Detroit daily newspapers are delivering their papers on only three days a week".

A) What are daily newspapers doing in Detroit only three days a week?
B) Where do daily newspapers are delivering their papers on only three days a week?
C) How often daily newspapers are delivering their papers on in Detroit?
D) Who are delivering their papers on only three days a week in Detroit?
E) How many days a week do daily newspapers are delivering their papers on in Detroit?