Asymptotic Branch Stars Are Important for Enriching the Interstellar Medium

Asymptotic branch stars are important for enriching the interstellar medium with heavy elements and molecules. Three of the following statements correctly describe reasons for this enrichment, and one does NOT. Which is the EXCEPTION?

A) These stars have relatively cool surfaces.
B) These stars have strong stellar winds.
C) These stars have convective zones that extend deep into the star.
D) These stars have shell fusion occurring just beneath the surface.