The correct answer is option A, that is, there was no life prior to Phanerozoic.
The Phanerozoic eon refers to the eon of visible life. It began about 541 million years ago. It signifies only one by an eighth of the time since the formation of Earth crust took place.
The Precambrian eon is older, and it extends from 4.6 billion years ago to the Phanerozoic eon. The fossils in the Precambrian eon are rare. It was in the late Precambrian eon that the origination of the first multi-cellular species took place.
