12 . Arrange the odd positive integers $1,3,5$, $7, \cdots$ into five columns, as shown in the table on the right. If the arrangement continues in the format of the table, the column in which 2001 is located, counting from the left, is ( ).
$\begin{array}{rrrrr} & 1 & 3 & 5 & 7 \\ 15 & 13 & 11 & 9 & \\ & 17 & 19 & 21 & 23 \\ 31 & 29 & 27 & 25 & \end{array}$
(A) first column
(B) second column
(C) third column
(D) fourth column
12.(B).

The numbers in the first column leave a remainder of 15 when divided by 16, the numbers in the second column leave a remainder of 1 or 13 when divided by 16, the numbers in the third column leave a remainder of 3 or 11 when divided by 16, the numbers in the fourth column leave a remainder of 5 or 9 when divided by 16, and the numbers in the fifth column leave a remainder of 7 when divided by 16. Since 2001 leaves a remainder of 1 when divided by 16, the answer is (B).