Not Much Physical Evidence of Life Is Available from Rocks

Not much physical evidence of life is available from rocks of the Precambrian because these ancient rocks:

A) have been greatly eroded in most areas.
B) have been deeply buried in most areas.
C) have been deposited in oceanic trenches deep in the oceans.
D) occupy inaccessible areas of mountainous regions.
E) occupy the polar regions and are thus covered by glaciers.