The way that shadow puppet shadows have changed is: Shadows are now made using electric lamps instead of oil lamps.
Shadow puppet shows are a form of traditional storytelling and entertainment that involves the use of flat articulated cutout figures (shadow puppets) which are held between a source of light and a translucent screen or scrim.
The puppeteers manipulate the puppets to create the illusion of moving images on the screen, accompanied by music, narration, and sound effects.
Hence D is correct because Shadows are now made using electric lamps instead of oil lamps.