Which Method Did Not Contribute Significant Geologic Knowledge About the Rocks

Multiple Choice

Which method did not contribute significant geologic knowledge about the rocks, structures, and mineral deposits of the mid-ocean ridges?

A) deep diving submersibles traverses by manned and unmanned subs
B) geophysical surveys and soundings of the ocean floor
C) mapping of slices of ocean crust added to the continents by tectonic activity
D) remote sensing and mapping of mineral deposits by satellites