Final answer:
The Frankfurt Parliament in October 1848 ultimately supported the idea of Kleindeutschland, which meant a smaller German state excluding Austria, and opting for leadership under Prussia.
Step-by-step explanation:
In October 1848, the Frankfurt Parliament faced a significant decision in the course of German unification. The delegates debated whether to include Austria in the unified German state, a concept known as Grossdeutschland, or to exclude Austria, favoring a Kleindeutschland solution, which would be a smaller German state primarily led by Prussia. After extensive debates, the Frankfurt Parliament opted for the Kleindeutschland approach. This was largely because including Austria and its diverse ethnicities would create a much larger and more unwieldy state, and there was also a need to exclude non-German territories from the unified Germany.