Hemingway's style can be best explained with his______.

A．an effort to protect an endangered marine species
B．the civilian use of a military detection system
C．the exposure of a U.S. Navy top-secret weapon
D．a new way to look into the behavior of blue whales

A．to trace and locate enemy vessels
B．to monitor deep-sea volcanic eruptions
C．to study the movement of ocean currents
D．to replace the global radio communications network