4. If the sides of a cyclic quadrilateral are 25, 39, 52, and 60, then the circumference of the circle is ( ).
(A) $62 \pi$
(B) $63 \pi$
(C) $64 \pi$
(D) $65 \pi$
4. (D).

Let $A B C D$ be a cyclic quadrilateral, and $A B=25$,
$$
B C=39, C D=52, D A
$$
$=60$. By the property of a cyclic quadrilateral, $\angle A=180^{\circ}-\angle C$. Connecting $B D$. By the cosine rule,
$$
\begin{aligned}
B D^{2} & =A B^{2}+A D^{2}-2 A B \cdot A D \cos \angle A \\
& =C B^{2}+C D^{2}-2 C B \cdot C D \cos \angle C,
\end{aligned}
$$

which means
$$
\begin{array}{l}
25^{2}+60^{2}-2 \cdot 25 \cdot 60 \cdot \cos \angle A \\
=39^{2}+52^{2}+2 \cdot 39 \cdot 52 \cdot \cos \angle A .
\end{array}
$$

Therefore, $\angle A=90^{\circ}, B D$ is the diameter of the circle.
$$
B D=\sqrt{25^{2}+60^{2}}=\sqrt{4225}=65 \text {. }
$$

Thus, the correct choice is (D).