Let $R$ be a commutative ring with 1 and $I$ and $J$ ideals of $R$. Choose the correct statement(s) from below:\\
(A) If $I$ or $J$ is maximal then $IJ = I \cap J$;\\
(B) If $IJ = I \cap J$, then $I$ or $J$ is maximal;\\
(C) If $IJ = I \cap J$, then $1 \in I + J$;\\
(D) If $1 \in I + J$ then $IJ = I \cap J$.