Answer:
In to
Explanation:
"Listening in" is a phrase used when you are turning on something, in some way, to listen to audio. So, you would be listening in to Timmy Turner's radio show.
Off-topic: Isn't Timmy Turner that one character from Fairy OddParents?
The correct answer should be A. He was occupied with making sure his sister did not repeat the same error, otherwise.
This should be the correct answer because placing otherwise here would create confusion in the sentence as it is not sure to what it refers.