Which phrase best completes the diagram?
A. Domesticated animals
B. Steel tools
C. Mathematics still used today
D. Sailing ships
![Which phrase best completes the diagram A Domesticated animalsB Steel toolsC Mathematics still used todayD Sailing ships class=](https://us-static.z-dn.net/files/d20/85c2896c1f663059ccd22efe212fd429.png)