The list below shows some events which took place at different periods in the geologic time scale.
1. Fish with craniums appear.
2. Mammals appear.
3. Sharks appear.
Which of these best orders the events from the earliest to the most recent?
Select one:
a. 1, 2, 3
b. 1, 3, 2
c. 2, 1, 3
d. 2, 3, 1