Teacher:In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.
Teacher: Now, understand the problem? Solve this instance: Question: Which of the dolphin and porpoise species that the great white sharks attack is the largest? Passage:White sharks also attack dolphins and porpoises from above, behind or below to avoid being detected by their echolocation. Targeted species include dusky dolphins (Lagenorhynchus obscurus), Risso's dolphins (Grampus griseus), bottlenose dolphins (Tursiops ssp.), Humpback dolphins (Sousa ssp.), harbour porpoises (Phocoena phocoena), and Dall's porpoises (Phocoenoides dalli). Groups of dolphins have occasionally been observed defending themselves from sharks with mobbing behaviour. White shark predation on other species of small cetacean has also been observed. In August 1989, a juvenile male pygmy sperm whale (Kogia breviceps) was found stranded in central California with a bite mark on its caudal peduncle from a great white shark. In addition, white sharks attack and prey upon beaked whales. Cases where an adult Stejneger's beaked whale (Mesoplodon stejnegeri), with a mean mass of around , and a juvenile Cuvier's beaked whale (Ziphius cavirostris), an individual estimated at , were hunted and killed by great white sharks have also been observed. When hunting sea turtles, they appear to simply bite through the carapace around a flipper, immobilizing the turtle. The heaviest species of bony fish, the oceanic sunfish (Mola mola), has been found in great white shark stomachs.
 Links: a. Stejneger's beaked whale b. Beaked whale c. Beaked whale d. Dusky dolphin
Student:
d