Definition: In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: Is Dover a port city? Passage:On 26 May 1940, Vivacious was chosen to participate in Operation Dynamo, the evacuation of Allied troops from Dunkirk, France, and she departed Dover that day in company with the light cruiser and the destroyers , , , , , and . She began patrols the following day to protect the evacuation beachhead from attacks by German aircraft and motor torpedo boats (S-boats, known to the Allies as "E-boats"). She made two trips from Dunkirk to Dover on 28 May 1940, evacuating 326 men on the first one and 359 on the second, and on 30 May 1940 she carried 537 more men from Dunkirk to Dover. German howitzers ashore fired on her on 31 May 1940 while she was off Bray-Dunes, France, inflicting 15 casualties on her crew. She took 427 more men from Dunkirk to Dover on 1 June 1940. She also took part in Operation OK on 3 June 1940, in which blockships were sunk to block the harbor at Dunkirk; she took aboard the crews of the sunken ships and brought them to Dover. One of those rescued from Dunkirk was the Rev Ivan Neill who would later become the Chaplain General.


b