Based on the given information, Lucy doesn't play a wind instrument, which would exclude the drums, bass, and flute since John and Mary are already assigned to those. Thus, Lucy must play the bass. However, if we consider that the fourth instrument mentioned after the three wind instruments is "trumped" (likely a typo for "trumpet"), which Pete is already playing, then Lucy could potentially play the bass or the drums. Since the drums are already taken, Lucy could be playing the bass, but without direct confirmation about her choice of instrument, we cannot decisively determine Lucy's instrument from this text.