The diagram depicts the atoms in a substance, with the atoms positioned at the corners of a cube. At a given temperature, the mean spacing between the atoms is $15\,\text{nm}$. If the temperature changes so that the mean spacing increases to $17\,\text{nm}$, by what factor does the density of the substance change?
- A0.61
- B0.69
- C0.78
- D0.88