3. The number of integers $x$ that satisfy $\frac{1}{\sqrt{3}-\sqrt{2}}<x<\frac{2}{\sqrt{6}-\sqrt{5}}$ is ( ).
(A) 4
(B) 5
(C) 6
(D) 7
3.C.
$$
\begin{array}{l}
3.1=1.7+1.4<\frac{1}{\sqrt{3}-\sqrt{2}} \\
=\sqrt{3}+\sqrt{2}<1.8+1.5=3.3, \\
9.2=2(2.4+2.2)<\frac{2}{\sqrt{6}-\sqrt{5}} \\
=2(\sqrt{6}+\sqrt{5})<2(2.5+2.3)=9.6 .
\end{array}
$$

Therefore, the integers $x$ that satisfy the conditions are $4,5,6,7,8,9$.