Plz answer read the following quote from otto von bismarck and then answer the question that follows.

we had to avoid wounding austria too severely; we had to avoid leaving behind in her any unnecessary bitterness of feeling or desire for revenge; we ought rather to reserve the possibility of becoming friends again with our adversary of the moment, and in any case to regard the austrian state as a piece on the european chessboard. if austria were severely injured, she would become the ally of france and of every other opponent of ours; she would even sacrifice her anti-russian interests for the sake of revenge on prussia. . the acquisition of provinces like austria silesia and portions of bohemia could not strengthen the prussian state; it would not lead to an amalgamation of german austria with prussia, and vienna could not be governed from berlin as a mere dependency. . austria's conflict and rivalry with us was no more culpable than ours with her; our task was the establishment or foundation of german national unity under the leadership of the king of prussia.

which argument is otto von bismarck making in this excerpt?
a. he is insisting that german unification should be the force that unites all german speakers in europe.
b. he is offering to defend german austria from bohemian nationalism in the austro-hungarian empire.
c. he is rejecting the idea that german austria should be made a part of a future united germany.
d. he is warning the prussian king not to go to war with austria over russian territory.