Short Term Earthquake Prediction Research Has Focused on _______

Short term earthquake prediction research has focused on _______.

A) measuring the rate of motion on various faults and the strength of the rocks along the faults to determine when the stress buildup will exceed the strength of the rocks
B) measuring vertical changes in elevation along faults to determine whether a fault zone is inflating before a major rupture
C) looking for precursors such as changes in topography, animal behavior, foreshocks, radon emission, etc., that might signal an imminent earthquake
D) looking at when and where earthquakes have occurred in the past to develop a model for the timing of future earthquakes