Ph= - log [H+] = -log 1.00× 10-7 = -(log 1 + log 10-7) = -( 0 + (-7log 10) = -( -7) = 7
Since there are no given items, I will give a general answer. Energy....or the lack of it. Examples: Heat, electricity, force (when an item is moving and it impacts something, it heats up...friction is an example of this), etc
The best option i think is b would be my best answer