If the direct speech is part of a larger sentence, which is the case here, the punctuation at the end of the direct speech is always a comma, regardless of whether it is a question or not.
And, sorry Danone, but "a" isn't going to make any sense if you would place it right there in the sentence
So, if I may, "How does one man read newspapers upsidedown while annihilating hamsters by the dozen," inquired the Chief Director, sipping plum enhancers all day long. "Why does
(Your "a" is still intact, Danone, just in another place
Computers, computers. So calculative, yet so incalculable.
3DS) Friend Code: 3523 - 2132 - 5743. Games: Kid Icarus: Uprising & Mario Kart 7.
Wii U) Nintendo ID: Decidetto.