10.16 If a computer executes the following program:
(1) Initial values $x=3, S=0$.
(2) $x=x+2$.
(3) $S=S+x$.
(4) If $S \geqslant 10000$, then proceed to 5; otherwise, continue from 2.
(5) Print $x$.
(6) Stop.

Then the value printed by statement 5 is
(A) 19.
(B) 21.
(C) 23.
(D) 199.
(E) 201.
(41st American High School Mathematics Examination, 1990)
[Solution] When $n=1,2, \cdots$, the values of $x, S$ are as follows:
\begin{tabular}{c|c|c|c|c|c|c|c}
\hline$n$ & 1 & 2 & 3 & 4 & $\cdots$ & $n$ & $\cdots$ \\
\hline$x$ & $3+2$ & $3+2 \cdot 2$ & $3+3 \cdot 2$ & $3+4 \cdot 2$ & $\cdots$ & $3+n \cdot 2$ & $\cdots$ \\
\hline$S$ & $3+2$ & $2 \cdot 3+3 \cdot 2$ & $3 \cdot 3+6 \cdot 2$ & $4 \cdot 3+10 \cdot 2$ & $\cdots$ & $n \cdot 3+\frac{n(n+1)}{2} \cdot 2$ & $\cdots$ \\
\hline
\end{tabular}
$\therefore \quad 3 \cdot n+\frac{n(n+1)}{2} \cdot 2 \geqslant 10000, \quad n$ is a positive integer,
Solving this, we get $n=99$, at this time $x=3+99 \cdot 2=201$.
Therefore, the answer is $(E)$.