3. If the equation $a^{x}-x-a=0$ has two real solutions, then the range of values for $a$ is ( ).
(A) $(1,+\infty)$
(B) $(0,1)$
(C) $(0,2)$
(D) $(0,+\infty)$
3. A.

Draw the graph, and you will find that when $a>1$, the function $y=a^{x}$ intersects with the function $y=x+a$ at two points.