Read the paragraph from Guillermo's essay.

From the Phoenicians to modern people, imagine the sheer number of people who have explored the upper reaches of the Earth's teeming oceans. Yet, relatively few have ventured into the vast mystery that awaits on the ocean floor. So far, the ocean has kept its secrets hidden, and its true bounty has remained a mystery.

Which phrase would benefit most from more precise word choice that also anticipates the readers' understanding?

A. "From the Phoenicians to modern people"
B. "the upper reaches of the Earth's teeming oceans"
C. "Yet, relatively few have ventured into the vast mystery"
D. "the ocean has kept its secrets hidden"