In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Q: Context: West Suffield Mountain is also an important raptor migration path. Link Information: the sedimentary rock of the ridge and surrounding terrain has produced equally significant evidence of prehistoric life in the form of Triassic and Jurassic fossils; in particular, dinosaur tracks Question: What dinosaurs migrated across West Suffield Mountain?

A: Answer: Triassic and Jurassic 
****
Q: Context: where it turns eastward and northeastward, flowing across the northern Great Plains past the city of Billings Link Information: none Question: Who is the current mayor of the city located on the northern Great Plains that the Yellowstone River flow through?

A: Answer: none
****
Q: Context: 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) Link Information: largest dusky dolphins have been encountered off the coast of Peru, where they are up to 210 cm (6 feet) in length  Question: Which of the dolphin and porpoise species that the great white sharks attack is the largest?

A:
Answer: bottlenose dolphin
****