Regular Languages are not closed under ______ operator.

1. Language a^{n}b^{n }is subset of a*b* but a^{n}b^{n }is not regular, hence regular is not closed under Subset operation 2. Σ* is regular language and every language is subset of Σ*, but all languages are not regular

https://cs.stackexchange.com/questions/34006/are-regular-languages-closed-under-division