Four cylinders of equal size, A, B, C and D, were taken from potatoes that had been kept for different periods of time. The cylinders were weighed, placed in $10\%$ salt solution for 45 minutes and then weighed again. The percentage change in mass was then worked out. Which cylinder had a water potential closest to that of the $10\%$ salt solution?
- A$-7.2$
- B$-2.5$
- C$-0.9$
- D$+3.4$