2. Among the following statements, the correct one is ( ).
(A) Natural numbers can be divided into prime numbers and composite numbers.
(B) Decimals all belong to rational numbers.
(C) Any rational number can be expressed in the form $\frac{n}{m}$ (where $m, n$ are integers, $m \neq 0$).
(D) Infinite decimals all belong to irrational numbers.