1. Condition A: The sum of the areas of two triangles and two corresponding sides are equal; Condition B: The two triangles are congruent. Then
A. A is the necessary and sufficient condition for B
B. A is the necessary condition for B
C. A is the sufficient condition for B
D. A is neither the necessary condition nor the sufficient condition for B
$S_{\triangle A B C}=\frac{1}{2} a b \sin C \Rightarrow C_{1}=C_{2}$ or $C_{1}=\pi-C_{2}$, thus A $\nRightarrow$ B, B $\Rightarrow$ A. A is a necessary condition for B, so the answer is $B$.