Final answer:
Option (4), Hugo Wolf is recognized for adapting Wagner's techniques to the German Lied, forging a significant connection between Wagner's operatic innovations and the art song.
Step-by-step explanation:
The composer best known for adapting Richard Wagner's methods to the German Lied is Hugo Wolf. Wolf's approach to the Lied was innovative and closely matched the intensification of expression and the embrace of thematic transformation that were characteristic of Wagner's music.
Hugo Wolf did not conform entirely to Classical traditions, and by incorporating Wagner's harmonic language and techniques, he expanded the scope and emotional range of the Lied.