Lacking any exposure to language before adolescence, a person will never master any language due to the of unused neural connections.

I believe the answer is: pruning

In psychological term, pruning is the process of eliminating a certain information from our brain in order to be replaced with the information that are deemed more necessary for our everyday use.
In language learning, pruning could happen when after we acquire the knowledge of new language but left them unused.

The answer should be b

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.