Q:I'm taking a test and have to guess the right answer to the question after the article. Article: Millions years ago much of our earth was covered with blocks of ice. These ice blocks were as tall as high buildings in modern cities. Most of the ice was in the northern part of the world. Then the ice blocks started to move south. Cold and rain came with the ice. Animals and people had to move. At last, the ice began to melt . After half a million years, most of it had melted. More than half of the earth became covered with water. The _ became much warmer. Things began to grow. The earth began to look the way it looks today. Question: The melting ice maybe helped to form _ . Options: A: mountains and valleys B: the sun, the moon and the earth C: cities and countries D: seas, lakes and rivers
A:
D