Read the passage carefully and answer the following question.
Geologists have been investigating a potential cycle in geological events for a long time. Back in the 1920s and 30s, scientists of the era had suggested that the geological record had a 30-million-year cycle, while in the 1980s and 90s researchers used the best-dated geological events at the time to give them a range of the length between 'pulses' of 26.2 to 30.6 million years. Now, everything seems to be in order -27.5 million years is right about where we'd expect. A study late last year suggested that this 27.5-million-year mark is when mass extinctions happen, too.
Which of the following statements can be BEST concluded from the passage?

The paragraph talks about how geological events occur in a cycle, and research has found the period of the cycle to be around 27.5million years. It also mentions that mass extinctions occur at this 27.5millions years, too.

From this we can see that geological events and mass extinctions both occur around the same time and thus are correlated to each other. Hence, option E is the answer.

Option A: the passage mentions that mass extinctions happen every 27.5million years, but it is not the main idea of the passage.

Option B: The passage says that the length between pulses is 26.2 and 30.6million years and in general occurs around 27.5million years. Thus, it is not a constant value.

Option C: It is incorrect since the paragraph only talks about mass extinction. Whether all species go extinct or not is not mentioned.

Option D: The passage is talking about geological events occurring in a cycle. Hence, it is incorrect.