What Technique Distinguished Jan Van Eyck's Artwork

What technique distinguished Jan van Eyck's artwork?

A) He learned how to apply oil paint in multiple thin layers and achieved finely detailed representations of every sort of surface, from stone to cloth, fur, and skin.
B) He was the first artist to accurately use perspective in order to depict subjects as if in real space.
C) He had studied human anatomy and therefore his human subjects appeared lifelike.
D) He mastered the medium of watercolor painting because he never found a patron and had to work on a budget.
E) His training as a sculptor enabled him to portray a three-dimensional effect.