Answer:
The correct answer would be two to three million years ago.
Step-by-step explanation:
The Quaternary glaciation, also known as the Pleistocene glaciation was the most recent ice age which began about 2.6 million years. Major extinctions event of large mammals or megafauna which include mammoth, mastodons, glyptodons and others began late in this ice age.
Thus, the correct answer would be two to three million years ago.