He asked whether such a thing was possible. The direct form for this sentence is:
AHe said "Is such a thing possible"?
BHe said, "Was such a thing possible"?
CHe said "Will such a thing be possible"?
DHe said "Whether such a thing was possible"?
AHe said "Is such a thing possible"?
BHe said, "Was such a thing possible"?
CHe said "Will such a thing be possible"?
DHe said "Whether such a thing was possible"?