3. In Rt $\triangle A B C$, $\angle C=90^{\circ}$, $C D$ is the altitude on the hypotenuse $A B$, and the inradii of Rt $\triangle A B C$, Rt $\triangle A C D$, and Rt $\triangle B C D$ are $r_{1}$, $r_{2}$, and $r_{3}$, respectively. Which of the following conclusions is correct? ( ).
(A) $r_{1}>r_{2}+r_{3}$
(B) $r_{1}=r_{2}+r_{3}$
(C) $r_{1}<r_{2}+r_{3}$
(D) Cannot be determined
3.C.

As shown in Figure 4, because
$$
\begin{array}{l}
r_{1}=\frac{A C+B C-A B}{2}, \\
r_{2}=\frac{A D+C D-A C}{2}, \\
r_{3}=\frac{B D+C D-B C}{2},
\end{array}
$$
$$
\begin{array}{l} 
\text { hence } r_{3}+r_{2}-r_{1} \\
=(A B+C D)- \\
(A C+B C) .
\end{array}
$$

By the Pythagorean theorem and the area formula, we know
$$
\begin{array}{l}
A C^{2}+B C^{2}=A B^{2}, \\
A C \cdot B C=A B \cdot C D .
\end{array}
$$

Then \( A C^{2}+B C^{2}+2 A C \cdot B C = 0 \) \\
\Rightarrow r_{3}+r_{2}-r_{1}>0 .
\end{array}
$$