(2) Let $A$ be a sufficient condition for $D$, $B$ be a sufficient condition for $C$, $D$ be a necessary condition for $C$, and $D$ be a sufficient condition for $B$. Try to answer:
(1) What kind of condition is $C$ for $D$?
(2) What kind of condition is $A$ for $B$?
(2) (1) Sufficient and Necessary Condition
(2) Sufficient Condition