The correct answer is:
A) They had some system of religious beliefs about afterlife.
Neanderthals are believed to have had some form of ritualistic behavior, which suggests they may have held beliefs related to the afterlife, as evidenced by burials and grave goods.
For the other options:
B) Incorrect. Neanderthals had brains that were, on average, as large as or larger than those of modern humans.
C) Incorrect. Neanderthals are a separate species that did not evolve into Homo sapiens; rather, they share a common ancestor with modern humans and coexisted with them for a period.
D) Incorrect. Neanderthals emerged well before the most recent ice age, with their appearance believed to be around 400,000 years ago.
Thus, A is the most accurate statement regarding Neanderthals.