Answer:
B. The last glacial maximum
Explanation:
The last glacial maximum occurred approximately 20,000 years ago. It was the latest phase in earth's geological history when the average temperature of the earth reached to the minimum and the land area covered by glaciers and ice sheets became maximum. As compared to the present time, there was three times more glacier ice on earth during this phase. The average global temperature of the earth was 6 degrees less than the present average global temperature.
