The best answer there, as far as gaining the support of the working class, was that Bismarck offered benefits such as health care. Bismarck was not a socialist, but he recognized that if the German nation did not employ some of the ideas from socialism, the working classes would become a rebellious force within the nation. So he implemented the first program of what we in the USA today would call Social Security. There was a Health Insurance Bill introduced in 1883, an Accident Insurance Bill in 1884, an Old Age and Disability Insurance Bill in 1889, and further protections offered by the state.
Bismarck did also aim to suppress the Catholic Church with measures that were referred to as the Kulturkampf (Culture War). But that was because as a Protestant, he distrusted the loyalty of the Catholics in the German state.
The answer to this question is A he was looking for a route to the east
