4. A merchant bought $n$ (where $n$ is a prime number) televisions for $m$ yuan (where $m$ is a natural number). Two of these televisions were sold to a charitable organization at half the cost price, and the rest were sold in the store, each with a profit of 500 yuan. As a result, the merchant made a profit of 5500 yuan. The minimum value of $n$ is ( ).
(A) 11
(B) 13
(C) 17
(D) 19
4. (C).

From the problem, $\frac{m}{n}+(n \cdots-2)\left(\frac{m}{n}+506\right) \cdots 5500+m$.
Solving, we get $m=500 n(n-13)$.
Since $m>0$, then $n>13$, and the smallest prime number greater than 13 is 17. Therefore, the answer is (C).