$35 \cdot 52$ As shown in the figure, rectangle $A B C D$ is divided into six unequal squares, among which the area of the smallest square is equal to 1. Then the area of rectangle $A B C D$ is 
(A) 152.
(B) 143.
(C) 132.
(D) 108.
(Anhui Province, China, Junior High School Mathematics Competition, 1991)
[Solution] Let the side length of the bottom-right square be $x$, then the side lengths of the other squares are sequentially $x+1$, $x+2$, $x+3$ (as shown in the figure, the numbers in the figure represent the side lengths of the squares).

Clearly, $(x+2)+(x+3)=x+x+(x+1)$, thus
$$
x=4 \text {. }
$$

Then $S_{A B C D}=(3 x+1)(2 x+3)=143$.
Therefore, the answer is (B).