Let $K$ be the smallest subfield of $\mathbb{C}$ containing all the roots of unity. Choose the correct statement(s) from below:\\
(A) $\mathbb{C}$ is algebraic over $K$;\\
(B) $K$ has countably many elements;\\
(C) Irreducible polynomials in $K[X]$ do not have multiple roots;\\
(D) The characteristic of $K$ is zero.