Hey there! The answer is C.
A = 1w
We want to solve for 1 and therefore we must isolate 1. We thus need to get rid of the w on the right side of the equation. Therefore we must divide both sides of the equation by w.
A / w = 1w / w
Do some algebra
A / w = 1
And finally switch sides.
1 = A / w.
Therefore the answer is C.
~ Hope this helps you!