Researchers have found that in the past century and a half, there have been several periods of slowing Earth's speed, and this period will last about 5 years each time. More importantly, the slowing of the Earth's speed is accompanied by an increase in strong earthquakes. Based on this, the researchers concluded that the slowdown of the Earth's speed led to the frequent occurrence of strong earthquakes. Which of the following, if true, would most challenge the above conclusions? ["During the period when the earth's speed is slowing down, about 25-30 strong earthquakes occur each year, and about 15 during other periods.", "The number of volcanic eruptions during the period of slowing Earth's speed has not changed significantly compared to other periods.", "The slowing down of the earth's speed will change the length of the day and night, and the change in the length of the day and night will lead to the occurrence of strong global earthquakes.", "Slight changes in the Earth's core have slowed down the Earth's speed and also caused strong earthquakes worldwide."]