I did not mind what he was saying, he was only through his hat.

Solution (By Examveda Team)

Option A: talking nonsense
This is correct. The idiom "through his hat" means talking nonsense. When someone is speaking "through their hat," they are saying things that are not true or do not make sense.

Option B: talking ignorantly
This is incorrect. While talking ignorantly can sometimes overlap with talking nonsense, "through his hat" specifically refers to saying things that are nonsensical rather than just showing a lack of knowledge.

Option C: talking irresponsibly
This is incorrect. Talking irresponsibly means speaking in a way that lacks consideration for the consequences, which is not the specific meaning of "through his hat."

Option D: talking insultingly
This is incorrect. Talking insultingly means speaking in a manner that is offensive or rude, which is not the specific meaning of "through his hat."

Conclusion:
Option A is the correct answer because the idiom "through his hat" means talking nonsense. It refers to saying things that are not true or do not make sense, which fits the context of the sentence.