Students must work out the layering order of three liquids, P, Q and R, when they are placed one on top of another. They are told that the liquids do not mix. The diagrams illustrate how the density of liquid P is found. The table gives the densities of Q and R. Q has density $0.75\text{ g/cm}^3$ and R has density $1.1\text{ g/cm}^3$. The liquids are carefully poured into a tall beaker and left to settle. Which diagram shows the liquids in the correct settled order?