Answer
B
Work Step by Step
If you throw an object upward with an initial speed $v_0$, the object returns to the initial position with the same speed $v_0$, but moving downward (see conceptual question 16).
So, if you throw another object downward with the same speed $v_0$, and both objects land at the same time, it is necessary that you throw the second object in the moment that the first object is going through the initial position, but moving downward. Now, they will keep the same position and speed until they hit the ground.
