C Camera. I think this because you can make timelapses with cameras which makes it easy to see.
There are two atoms of potassium bonded to one atom of sulfur.
An energy crisis<span> is any significant (bottleneck; logistics; or price rise) in the supply of energy resources to an economy. In popular literature, it often refers to one of the energy sources used at a certain time and place, in particular those that supply national electricity grids or those used as fuel in vehicles.</span>
The stone's altitude at time
is given by

where
is the acceleration due to gravity. The stone reaches the ground when
:
