Graph D.
Charles's law states that at the same pressure, the Volumen of a gas is proportional to its temperature (absolute temperature).
This is
V = K T, where K is the constant of proportionallity.
You can also write it in the form
V1 / V2 = T1/ Ts
When Temperature rise Volumen rise in a proportional way. If Temperature doubles Volumen doubles, if Tempearature is decreases to on third, Volume will decrease to one third.