Mid-ocean ridges, such as the mid-Atlantic ridge, normally form when tectonic plates are:
1) converging
2) diverging
3) stationary
4) sliding past each other

2) diverging

Explanation:

Mid-ocean ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth's tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt.