8. Calculate: $1+2+3-4+5+6+7-8+\cdots+$ $197+198+199-200=(\quad)$.
(A) 9800
(B) 9900
(C) 10000
(D) 10100
(E) 10200
8. B.
$$
\begin{array}{l}
\text { Original expression }=(1+2+3+4+\cdots+197+198+ \\
199+200)-2 \times(4+8+\cdots+200) \\
=\frac{(1+200) \times 200}{2}-2 \times \frac{(4+200) \times 50}{2} \\
=9900 .
\end{array}
$$