5. The ellipse $\frac{x^{2}}{4}+\frac{y^{2}}{3}=1$ has $n$ different points $P_{1}, P_{2}, \ldots, P_{n}, F$ is the right focus, $\left\{\left|P_{i} F\right|\right.$ \} forms an arithmetic sequence with a common difference $d>\frac{1}{100}$. Then the maximum value of $n$ is ( ).
(A ) Fang data $) 200$
( C) 99
( D ) 100
5.( B ).
$$
\begin{array}{l}
\because\left|P_{n} F\right|=\left|P_{1} F\right|+(n-1) d, \\
\therefore n=1+\frac{\left|P_{n} F\right|-\left|P_{1} F\right|}{d} .
\end{array}
$$

In an ellipse, the maximum value of the focal radius $\left|P_{i} F\right|$ is $a+c$, and the minimum value is $a-c$, so
$$
\begin{array}{l}
\left|P_{n} F\right|-\left|P_{1} F\right| \leqslant a+c-(a-c)=2 c=2, \\
\text { hence } n \leqslant 1+\frac{2}{d}<1+2 \times 100=201 .
\end{array}
$$

Therefore, the maximum value of $n$ is 200.