Consider the following events.
1. First reptiles
2. First insects
3. Shelled animals
4. First mammals
Arrange the above events in chronological order of their origin on the earth and select the correct answer from the codes given below:

1. A.2, 1, 3, 4
2. B.2, 3, 1, 4
3. C.3, 2, 1, 4
4. D.2, 4, 1, 3