What record did the nereus break in may 2009? a. it became the first remote operated deep-sea robot. b. it dove to a depth of 6.8 miles. c. it explored an undersea mountain. d. it took the first videos of deep sea organisms.

I think the correct answer from the choices listed above is option B. Diving to a depth of 6.8 miles is the record that Nereus broke in May 2009.Nereus was a hybrid unmanned autonomous underwater vehicle (HROV, a type of remotely operated underwater vehicle) built by the Woods Hole Oceanographic Institution (WHOI).