Which statements about the degree of polymerisation are correct? (C = 12, H = 1, N = 14, O = 16)

1. AFor an addition polymer made of monomer M, $DP=M_{\text{polymer}}/M_{\text{monomer}}$ (ignoring end groups)
2. BThe repeat unit of nylon 6,6, $\mathrm{C}{}_{12}\mathrm{H}{}_{22}\mathrm{N}{}_2\mathrm{O}{}_2$, has a mass of 226, equal to the monomers' total mass minus that of two $\mathrm{H}{}_2\mathrm{O}$
3. CA polythene sample with $M_n=1.4\times 10^5\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ has $D{P}_n=5000$
4. DAll chains in a sample of synthetic polythene have the same degree of polymerisation