Poly(propene) is classed as an addition polymer. What are the $\text{C-C-C}$ bond angles in its polymer chain?
- AThey are all $109^{\circ}$.
- BHalf of them are $109^{\circ}$ and half are $120^{\circ}$.
- CHalf of them are $90^{\circ}$ and half are $180^{\circ}$.
- DThey are all $120^{\circ}$.