Leitmotivs (Leitmotifs), which were developed by the composer Richard Wagner, were first used in operas for what purpose? A. To change the emotion of the scene
B. To add background music to movies
C. As harmony to the singers
D. As character "Theme Songs"

i think it is A

Explanation:

(Wagner's) goal was a new type of stage work that should carry dramatic conviction through music Out of the application of his theories arose...the new place of dominance in opera given to the orchestra It was not a symphonic ensemble that existed for the creation of musical beauty in terms of form. It was not an accompaniment for a drama. It was the drama