3. Given a linear function $y=k x+b$, where $k b>$ 0. Then the graph of all linear functions that meet the conditions must pass through ( ).
(A) the first and second quadrants
(B) the second and third quadrants
(C) the third and fourth quadrants
(D) the first and fourth quadrants
3. B.

From $k b>0$, we know that $k$ and $b$ have the same sign.
When $k$ and $b$ are both positive, the graph of the linear function passes through the first, second, and third quadrants;

When $k$ and $b$ are both negative, the graph of the linear function passes through the second, third, and fourth quadrants.

Therefore, the graph of the linear function that meets the conditions must pass through the second and third quadrants.