$35 \cdot 38$ When 6 chords are drawn in a circle, dividing the circular area into $n$ planar sections, the maximum value of $n$ is
(A) 18.
(B) 22.
(C) 24.
(D) 32.
(China Partial Provinces and Cities Junior High School Mathematics Correspondence Competition, 1990)
［Solution］From the following division, we can find:
$$
\begin{array}{llrc}
1+1 & 1+1+2 & 1+1+2+3 & 1+1+2+3+4 \\
(n=1) & (n=2) & (n=3) & (n=4)
\end{array}
$$
.....

At the $k$-th step, adding one more chord is equivalent to dividing the circle into $k$ more parts, so $k$ chords can divide the circle into at most
$$
n=1+1+2+3+\cdots+k=\frac{k(k+1)}{2}+1 \text { (parts). }
$$
When $k=6$, we get $n=22$.
Therefore, the answer is $(B)$.