In the following picture, E is going to slide the object down and as per the terrain and the physics, the round object is going to travel all the way till the end. Now, can you analyze who all people will die when it happens?
As you can see, the person at D dies straight through the object directly. The object then travels further and the see saw thing kills the person at the C as it has spikes below that. Upon falling, over the see saw, the blue object lifts up and then kill the person at B.The solution ends here, but just for fun, The E stands for Ebola and thus the person at A dies as well.Thanks to 9gag for this gif.