This is an example of a failure of deductive reasoning.
Explanation:
Deductive reasoning is one that first analyzes two premises to reach a conclusion. If the text shown in the question above were an example of deductive reasoning done correctly, we should read: "we do not know B, nor C and therefore we cannot say that they are equal to A."
However, we see the narrator of the text presenting conclusions without evaluating the premises, presenting a false conclusion. This is an example of inductive reasoning failure.