1. If $x$ takes real values, then the minimum value of $\sqrt{4 x^{2}+4 x+1}+$ $\sqrt{4 x^{2}-7984 x+1996^{2}}$ is ( ).
(A) 0
(B) 1995
(C) 1996
(D) 1997
$\begin{array}{l}\text { I. 1. (D). } \\ \text { Original expression }=|2 x+1|+|2 x-1996| . \\ \text { When } x<-\frac{1}{2} \text { or } x>998 . \\ \text { When } x<-\frac{1}{2} \text {, } \\ \text { the expression }=-(2 x+1)-(2 x-1996)>1997 . \\ \text { When } x>998 \text {, } \\ \text { the expression }=2 x+1+2 x-1996>1997 . \\ \text { When }-\frac{1}{2} \leqslant x \leqslant 998 \text {, } \\ \text { the expression }=2 x+1+1996-2 x=1997 . \\ \text { When } x>998 \text {, } \\ \text { the expression }=2 x+1+2 x-1996>1997 .\end{array}$