Why is B correct? Why is A incorrect?

Hi @Ryan-Mahabir, (A) is incorrect because although we do know that the token system was replaced, we're not explicitly given a reason for why it was replaced, nor can we infer a reason based on the passage. The lines pertaining to the removal are from 38-40; note that no reason is given in those lines or around them. (B) is supported by lines 35-37. Note that as the crafts got more complicated, new symbols were made to encompass objects such as bowls or jars with handles. Hope this helps!