B should be the answer
Look at this example to help you
It depends, What is the balloon filled with? Just air, heilum, water, etc. If its just air then the bowling ball would most likly hit first, but if the balloon is filled with water it would problably hit at the same time, theres also air resistace to think about is there any or it is almost like a vaccum chamber?
I think it’s 15cm
Might be 7cm