P, Q, R and S are four organic compounds. P is an unsaturated hydrocarbon. Q combusts but is otherwise unreactive. R has a $\text{C-C}$ single bond and a $\text{C=C}$ double bond. S undergoes addition polymerisation. Which of the compounds are alkenes?
- AP and R only
- BP, R and S
- CP, Q and S
- DQ, R and S