I'm not so good at science but I believe just from the Internet and common sense that it could be found in Hawaii, Yellowstone, Iceland, and (not completely sure for last one) but maybe Pompeii. I know the first 3 are most likely correct but I'm not completely sure about Pompeii. Just look it up, lol
the world's current population is 7.3 billion and the world population in 1915 was 1.8 billion. The increase over the past century is 7.3 billion - 1.8 billion = 5.5 billion. So, the correct answer would be "more than 5 billion" (option D).
