It can be inferred from the passage that the theory employed by the investigators mentioned in the second paragraph would lead one to predict that which one of the following would result from the addition of a grain of sand to a sandpile? A. The grain of sand would never cause anything more than a minor disturbance. B. The grain of sand would usually cause a minor disturbance, but would occasionally cause a small avalanche. C. The grain of sand would usually cause either minor disturbance or a small avalanche, but would occasionally cause a catastrophic event. D. The grain of sand would usually cause a catastrophic event, but would occasionally cause only a small avalanche or an event more minor disturbance. E. The grain of sand would invariably cause a catastrophic event.