What Defines the Habitable Zone Around a Star

Multiple Choice

What defines the habitable zone around a star?

A) the region around a star where rocky planets can form
B) the region around a star outside of its hot, tenuous corona
C) the region around a star where its ultraviolet radiation is too weak to destroy biological organisms on a planetary surface
D) the region around a star where liquid water can exist on planetary surfaces
E) the region around a star where humans can survive