3. Given the sequences $\left\{a_{n}\right\} 、\left\{b_{n}\right\}$, for any $n \in \mathbf{Z}_{+}$, it holds that $a_{n}>b_{n}$. As $n \rightarrow+\infty$, the limits of the sequences $\left\{a_{n}\right\} 、\left\{b_{n}\right\}$ are $A 、 B$ respectively. Then ( ).
(A) $A>B$
(B) $A \geqslant B$
(C) $A \neq B$
(D) The relationship between $A$ and $B$ is uncertain
3. B.

If we take $a_{n}=\frac{1}{n}, b_{n}=\frac{1}{n+1}$, then $a_{n}>b_{n}$.
And $\lim _{n \rightarrow+\infty} a_{n}=\lim _{n \rightarrow+\infty} b_{n}=0$, so $A>B$ is not necessarily true, but it can ensure that $A \geqslant B$.