2. If $a<b$ then $\sqrt{-(x+a)^{3}(x+b)}$ equals
(A) $(x+a) \sqrt{-(x+a)(x+b)}$;
(B) $(x+a) \sqrt{(x+a)(x+b)}$;
(C) $-(x+a) \sqrt{-(x+a)(x+b)}$;
(D) $-(x+a) \sqrt{(x+a)(x+b)}$.
2. (C)
$$
\text { Sol } \begin{aligned}
& \because \quad-(x+a)^{3}(x+b) \geqslant 0, \\
& \therefore \quad(x+a)(x+b) \leqslant 0 . \\
\text { Also } & \because \quad a<b, \\
& \therefore \quad-b \leqslant x \leqslant-a . \\
& \therefore \quad \text { Original expression }=-(x+a) \sqrt{-(x+a)(x+b)} .
\end{aligned}
$$