The graph plots observed landslide events relative to the duration and rate of rain that happened before the event. Based on the information contained in the
graph

A) land surfaces with a steeper slope require less rain to start a landslide than shallower slopes.

B) no clear correlation exists between the duration and rate of rainfall and the occurrence of a landslide.

C) landslides after rain of a longer duration tend to be larger than those after shorter rain events.

D) if a rain event leading to a landslide was short in duration, the rain rate tended to be much higher than for other events.