What Evidence Best Supports the Independent Gain of Gyri and Sulci

What evidence best supports the independent gain of gyri and sulci in neocortex multiple times in the mammalian lineage?

A) Species in all three branches of mammals (monotremes, marsupials, and placental mammals) have gyri and sulci.
B) Species in all three branches of mammals (monotremes, marsupials, and placental mammals) lack gyri and sulci.
C) Reptiles, the outgroup of mammals, do not have gyri, sulci, or neocortex.
D) Larger mammalian brains are more likely to have gyri and sulci.
E) Smaller mammalian brains are less likely to have gyri and sulci.