This strengthens the argument by reducing the possibility that the tools were used for something other than hunting. If the sharpened wooden poles weren’t for self-defense or cutting and scavenging carcasses, they’re more likely to have been used for hunting.

We know that the humanlike inhabitants of northern Europe likely used these tools, but we’re still unsure how they were used. We don’t know if they were really for hunting or for something else.

Even if Homo sapiens did evolve from humanlike precursors 200,000 years earlier than is normally assumed, we don’t know that they then inhabited northern Europe. Regardless, (C) doesn’t strengthen the author’s hypothesis that the humanlike precursors were hunters.

Irrelevant— this doesn’t address the tools found in northern Europe or support the hypothesis that those tools were used by humanlike precursors for hunting.

The argument is addressing the humanlike precursors of Homo sapiens, not prehistoric Homo sapiens. Either way, just because these prehistoric Homo sapiens didn’t abandon scavenging and gathering doesn’t mean that they didn’t also hunt with sharpened wooden sticks.