Taryn lives near the ocean and often goes to the shore with her parents. She has never ventured too far out to sea but has always been curious about how scientists study deeper water and the shape of the ocean floor near her home. Which modern technology would she MOST likely research to understand more about this?

diving bells because they transport humans to the ocean floor
Aquarius because it researches coral bleaching
an acoustic Doppler current profiler (ADCP), which reads echos
multi-beam and single-beam surveys, which send out sonar

pulses to map the ocean floor