$100\times 19.98\times 1.998\times 1000=$
$\text{(A)}\ (1.998)^2 \qquad \text{(B)}\ (19.98)^2 \qquad \text{(C)}\ (199.8)^2 \qquad \text{(D)}\ (1998)^2 \qquad \text{(E)}\ (19980)^2$
$19.98\times100=1998$
$1.998\times1000=1998$
$1998\times1998=(1998)^2=\boxed{D}$