What did you choose?
( What ( ( ( did you ) choose ) ? ) )
(ROOT (SBARQ (WHNP (WP What)) (SQ (VBD did) (NP (PRP you)) (VP (VB choose))) (. ?)))
Which one did you pick?
( ( Which one ) ( ( ( did you ) pick ) ? ) )
(ROOT (SBARQ (WHNP (WDT Which) (NN one)) (SQ (VBD did) (NP (PRP you)) (VP (VB pick))) (. ?)))