The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
Bismarck succeeded against internal and external opposition because he was a great leader and a proven military officer that had the conviction of uniting the distinct ethnicities and states that formed the Germanic people in those years. He always thought that the unification of the Germanic tries would represent a more solid nation and a stronger front against their enemies. That is why he unified the states and formed Prussia in 1867.
Although Bismarck was a man with conservative ideas, he applied a series of reforms such as the establishment of a welfare state, the vote for men, the modernization of the country, and the pacification of the region.