In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Among the entities, try to find the best entity that is most likely to fill in "_" and classify the answers based on options.
Q: A new attack submarine being tested by United States Navy has been given a special guard of honour - by a pod of dolphins. The nuclear powered, deep ocean sub was put through its paces off the coast of Newport, Virginia, on May 26 when the playful mammals were spotted leaping out of the water just a few feet from the front of it. The incredible footage of the dolphins - leaping in front of the new Virginia-class attack sub completing its sea trials - has been seen by hundreds of thousands of people since it went viral. Attack submarines are designed to seek and destroy enemy submarines and surface ships and carry Tomahawk cruise missiles to project ashore. They are also used for reconnaissance missions and sea mine warfare.US Navy was sea testing its latest nuclear powered deep ocean submarinePlayful mammals spotted leaping out of the water a few feet in front of itDolphins often swim by boats but one of first times photographed by sub 
 Questions:_ are able to cruise through the water at high speed and experts believe that the intelligent animals may use the wake from a boat as a speed boost. (A) United States Navy (B) Newport (C) Virginia (D) Tomahawk (E) US Navy (F) Dolphins
A: 
(F)