Correct option is A
Explanation -
Geological time is divided into a nested hierarchy that helps geologists and paleontologists describe the timing and relationships of events in Earth’s history.
Here is the correct chronological hierarchy from largest to smallest unit:
Eon - The largest division of geological time. Only 4 are recognized: Hadean, Archean, Proterozoic, and Phanerozoic.
Era - Subdivision of an eon (e.g., Mesozoic, Cenozoic).
Period - Subdivision of an era (e.g., Jurassic, Cretaceous).
Epoch - Subdivision of a period (e.g., Holocene, Pleistocene).
So, the correct answer is option a -
Eon > Era > Period > Epoch
