One pound of feathers would be easier weighing than one pound of iron

It would be harder, since feathers are lighter than iron, you would need a lot more of them , which could make it harder to weigh them.

I’m guessing that the answer is c, but i’m not sure which grid is being talked about. since 5x5= 25 and 3x3= 9 (which there are no answers for). a is not right because while the ratio is the same, 6/25= 0.24 which is equal to 24% not 30%.