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: How many people live in the city where Kirdorf was born? Passage:Emil Kirdorf was born at Mettmann, Rhine Province. His father was a wealthy owner of a weaving mill. He had a brother named Adolf who would be his business partner during his adult life. Kirdorf volunteered a year in 1864 in Hamburg to work in an export enterprise. A year later, he worked in a textile company in Krefeld. The family's mill went bankrupt, mainly because of the management's refusal to introduce mechanical looms. Kirdorf therefore changed to mining industry in which he worked as an accountant. Following the Franco-Prussian War, he became director of Zeche Holland in 1871. Two years later, the entrepreneur Friedrich Grillo offered him the position of commercial director in the Gelsenkirchener Bergwerks-AG (GBAG) company. He became general manager of GBAG in 1893. He steered the company through the Long Depression of the 1870s, and held this position until 1926.


a