Combining atoms at room temperature may be possible one day, but such a feat has never been verifiably performed.

(A) Combining atoms at room temperature may be possible one day
(B) One day, it may be possible to combine atoms at the temperature of a room
(C) The combination of atoms at room temperature may one day be possible
(D) It may one day be possible to combine atoms at room temperature
(E) Combining atoms at room temperature may one day be possible

OA is D.

What is wrong with A?