Being Naughty and Doing Exactly as Told

I heard there was a time-out tonight because BH put a small toy part in his mouth and went running.

He knows better than that but he is so stubborn these days.

As usual, he cried when he got a time-out and to help him understand (not that he doesn't) why he got put in, H1 asked him if he knew why he got put there.

"Tell me why," she said.

"Why," he answered.

I'm not too clear if was "Why" or "Y" he responded with.