With All the Evidence for Neandertals and Humans Being Different

With all the evidence for Neandertals and humans being different species,why is there still debate about their evolutionary relationship?

A) Neandertal culture has many similarities with early human culture.
B) Their mtDNA suggests that they were very closely related.
C) Many scientists doubt the validity of the genetic evidence.
D) The cultural evidence and the anatomical evidence seem to conflict.