6. There are 10 numbers: $1983^{3}+3 \times 1983^{2}+2 \times$ $1983,1984^{3}+3 \times 1984^{2}+2 \times 1984, \cdots, 1991^{3}$ $+3 \times 1991^{2}+2 \times 1991,1992^{3}+3 \times 1992^{2}+2$ $\times 1992$, among the following integers, the largest integer that can divide each of the 10 numbers is ( ).
(A) 2
(B) 3
(C) 6
(D) 12
$6 . C$